Background

Windows are available in a wide variety of sizes and can include e.g. one or more movable sashes that can be slidably opened to allow airflow into the interior of a building. However, in many locations, the outside air may contain undesirable pollution or contaminants. It may thus be desirable to filter air that passes into a building through a window opening.

Summary

In broad summary, herein is disclosed a window air filter apparatus that comprises a first, base unit and a second, movable unit and that includes at least one magnetic attachment element that is attachable to a complementary magnetic attachment element of a window. These and other aspects will be apparent from the detailed description below. In no event, however, should this broad summary be construed to limit the claimable subject matter, whether such subject matter is presented in claims in the application as initially filed or in claims that are amended or otherwise presented in prosecution.

Brief Description of the Drawings

Fig. 1 is a perspective interior view of an exemplary window air filter apparatus, in a first, unexpanded condition.

Fig. 2 is a perspective exterior view of an exemplary window air filter apparatus, in a first, unexpanded condition.

Fig. 3 is a perspective interior view of an exemplary window air filter apparatus, in a second, expanded condition.

Fig. 4 is a perspective exterior view of an exemplary window air filter apparatus, in a second, expanded condition.

Fig. 5 is a perspective exploded interior view of an exemplary base unit and movable unit of a window air filter apparatus.

Fig. 6 is a perspective exploded exterior view of an exemplary base unit and movable unit of a window air filter apparatus.

Fig. 7 is a bottom view of an exemplary window air filter apparatus.

Fig. 8 is an interior view of an exemplary window air filter apparatus, with interior walls of the apparatus housing omitted.

Fig. 9 is a top perspective cross-sectional view of an exemplary window air filter apparatus.

Fig. 10 is an interior view of a portion of an exemplary window air filter apparatus, with interior walls of the apparatus housing omitted.

Fig. 11 is an idealized side view of an exemplary window air filter that is magnetically mounted to a window. Fig. 12 is a side view of an exemplary window air filter that is magnetically mounted to a window.

Fig. 13 is a perspective interior view of an exemplary window air filter that is magnetically mounted to a window.

Fig. 15 is an interior perspective view of an exemplary window air filter apparatus installed in a horizontal sash window.

Like reference numbers in the various figures indicate like elements. Some elements may be present in identical or equivalent multiples; in such cases only one or more representative elements may be designated by a reference number but it will be understood that such reference numbers apply to all such identical elements. Unless otherwise indicated, all figures and drawings in this document are not to scale and are chosen for the purpose of illustrating different embodiments of the invention. In particular the dimensions of the various components are depicted in illustrative terms only, and no relationship between the dimensions of the various components should be inferred from the drawings, unless so indicated.

As used herein as a modifier to a property or attribute, the term "generally", unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring a high degree of approximation (e.g., within +/- 20 % for quantifiable properties). The term "substantially", unless otherwise specifically defined, means to a high degree of approximation (e.g., within +/- 10% for quantifiable properties). The term "essentially" means to a very high degree of approximation (e.g., within plus or minus 2 % for quantifiable properties). It will be understood that the phrase "at least essentially" subsumes the specific case of an "exact" match. However, even an "exact" match, or any other characterization using terms such as e.g. same, equal, identical, uniform, constant, and the like, will be understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match. All references herein to numerical parameters (dimensions, ratios, and so on) are understood to be calculable (unless otherwise noted) by the use of average values derived from a number of measurements of the parameter.

Detailed Description

Glossary

The following terminology is used in describing a window air filter apparatus that can be installed in a sash window of a building:

Terms such as interior and exterior and the like are defined with respect to the window and building; interior means toward a room in which window the air filter apparatus is installed; exterior means away from the room. By way of specific example, an interior side of the window air filter apparatus faces toward a room of the building; an exterior side of the window air filter apparatus faces away from the room and is in contact with environmental air that is desired to be filtered as it passes into the room.

Terms such as inside, outside, inward, outward, and the like, are defined with respect to the air filter apparatus; terms such as inward, inside, and the like denote a direction toward the geometric center of the air filter apparatus. Terms such as outward, outside and the like denote a direction away from the geometric center of the air filter apparatus.

The term longitudinal denotes a direction (L) along the long axis of an air filter apparatus. As installed in a sash window, the longitudinal axis of the air filter apparatus will be orthogonal to the direction of slidable movement of a movable sash of the sash window. In the case of a horizontal sash window (in which case the movable sash is movable back and forth in a horizontal direction with respect to the Earth), the longitudinal direction of the apparatus will be at least generally aligned with the vertical direction with respect to the Earth. The transverse direction (T) of an air filter apparatus is orthogonal to the longitudinal direction of the apparatus and is at least generally aligned with the direction of slidable movement of a movable sash in a window in which the apparatus is installed. The transverse direction can be considered to be the "width" direction of the apparatus as installed. The thickness direction (Th) of an air filter apparatus is orthogonal to the longitudinal direction of the apparatus and is orthogonal to the transverse direction of the apparatus. As installed in a sash window, the thickness direction of the apparatus is at least generally aligned with an interior-exterior axis of the window. The longitudinal direction (L), the transverse direction (T), and the thickness direction (Th) are shown for an exemplary air filter apparatus installed in a horizontal sash window in Fig. 15.

Terms such as upper, lower, upward, downward, above, below and the like are applied to an air filter apparatus installed in a horizontal sash window with the longitudinal axis of the apparatus being at least generally vertically aligned relative to the Earth, and have their customary meaning.

Disclosed herein is a window air filter apparatus 10, comprising a first, base unit 20 and a second, movable unit 60, and comprising an air filter assembly comprising an air filter media. The second, movable unit 60 is reversibly slidably movable back and forth relative to the first, base unit 20 between at least a first, unexpanded configuration and a second, expanded configuration. Apparatus 10 is configured to be self-retaining in the second, expanded configuration (and also in any partially expanded

configuration) as discussed in detail later herein. An exemplary apparatus 10 is shown in a first, unexpanded configuration in interior view (i.e., a view from within a room in a window of which the apparatus is installed) in Fig. 1 and in exterior view (i.e., a view from outside a room in a window of which the apparatus is installed) in Fig. 2. Apparatus 10 is shown in a second, expanded configuration in interior view in Fig. 3 and in exterior view in Fig. 4.

Base unit 20 comprises a lower, pedestal portion 36 and an upper, riser portion 25 as can be seen in the interior view of Fig. 5, in which movable unit 60 is exploded away from base unit 20. In some embodiments, portions 36 and 25 may be integral with each other, meaning that they are of the same composition and were made together as a single piece, at the same time in the same operation (e.g., an injection molding operation). In other embodiments, portions 36 and 25 may be made separately and then attached together in the manufacturing of apparatus 10. Movable unit 60 comprises an upper, shroud portion 75 and a lower, sleeve portion 65 as can be seen in Fig. 5. Portions 75 and 65 may be integral with each other, or may be separately made and attached together.

Base unit 20 and movable unit 60 may each comprise a main body (e.g., a housing) that is made e.g. of molded plastic, to which main body various additional components (e.g. one or more

weathershields, resilient layers, air conduits, fittings, brakes, speed limiters, and so on) may be attached. As is evident from Figs. 1, 5, and 6, when apparatus 10 is in an unexpanded condition, shroud portion 75 of movable unit 60 outwardly overlies and surrounds riser portion 25 of base unit 20. When apparatus 10 is in this unexpanded condition, sleeve portion 65 of movable unit 60 outwardly overlies pedestal portion 36 of base unit 20, on the exterior side 24 of base unit 20 and on a major portion of the transverse sides 66 of base unit 20. (Sleeve portion 65 is three-sided with an interior side being omitted so as to not block the flow of filtered air from fan 117 toward filter-air outlet 31, as will be appreciated e.g. from inspection of Figs. 5 and 8.)

Base unit 20 and movable unit 60 may each exhibit a longitudinal axis and a transverse axis, the longitudinal axis of the base unit and the longitudinal axis of the movable unit being aligned with each other so as to define a longitudinal axis (L) of the window air filter apparatus 10, as shown in Fig. 15. In many embodiments, the direction along which movable unit 60 is reversibly slidably movable relative to base unit 20 is at least substantially aligned with the longitudinal axis (L) of the window air filter apparatus, as will be evident from e.g. Figs 1 and 3.

When apparatus 10 is in an expanded condition, a portion of interior side 21 of riser portion 25 of base unit 20 may be exposed, as shown in Fig. 3; also, exterior side 24 of lower, pedestal portion 36 of base unit 20 may be exposed, as shown in Fig. 4. Thus, the interior (i.e., room-facing) side of apparatus 10 is provided by portions of walls of interior side 61 of movable unit 60 and of interior side 21 of base unit 20, as seen in Figs. 1 and 3. The exterior side (that faces e.g. outside into the environment) of apparatus 10 is provided by walls of exterior side 64 of movable unit 60 and by portions of walls of exterior side 24 of base unit 20, as seen in Figs. 2 and 4.

The exterior side of apparatus 10 may be exposed to environmental conditions such as rain, snow, hail, windblown debris, and so on. Accordingly, it will be appreciated that the design of apparatus 10, in which the exterior walls and transverse walls of base unit 20 and of movable unit 60 that are exposed to the environment are at least generally solid (e.g., with few or no unoccluded through-holes extending therethrough, except for e.g. an air inlet 71 as described later), and in which the exterior wall and transverse walls of movable unit 60 outwardly overlie the exterior wall and transverse walls of base unit 20, enhance the ability of these walls to minimize or prevent the entry of e.g. rain or snow into apparatus 10. Movable unit 60 comprises a filter assembly 250 (seen most easily in Fig. 10) for filtering air. Accordingly, an exterior-air inlet (e.g., an opening) 71 is provided e.g. on an upper portion of exterior face 64 of shroud portion 75 of movable unit 60, as seen in Fig. 2. This exterior-air inlet may be exteriorly covered by a weathershield 72 (which may be provided e.g. a solid layer as in the exemplary design of Figs. 2 and 4, or which may be collectively provided by a set of louvers or the like) that at least substantially prevents the entry of e.g. liquid water into the exterior-air inlet. In particular, weathershield 72 may be shielded or enclosed at its upper end e.g. to prevent downwardly-moving rain water from entering the exterior-air inlet.

In some embodiments, window air filter apparatus 10 is a powered air filter apparatus. In such embodiments, base unit 20 can comprise a fan 117 (as shown in exemplary embodiment e.g. in Fig. 8) for drawing exterior air in through exterior-air inlet 71 and through the filter media of air filter assembly 250, and expelling the filtered air into a room through filtered-air outlet 31 of base unit 20. Filtered-air outlet 31 may be located e.g. on the interior (room-facing) side 21 of lower, pedestal portion 36 of base unit 20; if desired, a cover 32 may be provided interiorly of filtered-air outlet 31, as shown in exemplary embodiment in Fig. 1. A fluidic connection must thus be provided between filter assembly 250 and fan 117; furthermore, this fluidic connection must allow the required movability of unit 60 and unit 20 relative to each other (while descriptions herein speak of moving unit 60 relative to unit 20, it will be appreciated that either unit can be moved relative to the other if desired). In order for this to be achieved, fan 117 and air filter assembly 250 are fluidically connected to each other by a conduit that includes at least one reversibly expandable and contractible section. This allows the second, movable unit to be reversibly slidably moved back and forth between the first, unexpanded configuration and the second, expanded configuration while maintaining the fluidic connection between the fan and the air filter.

As shown in exemplary embodiment in Figs. 8 and 10, the fluidic connection between fan 117 and filter assembly 250 can be provided by a conduit that includes an air-receiving receptacle 112 that receives air that passes through filter media 255, which receptacle comprises an outlet fitting 113 that is mated to an upstream end of a hollow tube (hose) 114. The downstream end of tube 114 can be mated to an inlet fitting that is provided in a partition 115, which inlet fitting allows air to enter a fan chamber 116 containing fan 117. In some embodiments, hollow tube 114 may be reversibly expandable and contractible along its long axis (for example, tube 114 may be accordionized as shown in Figs. 8 and 10 to facilitate such expansion and contraction). This can allow units 60 and 20 to be moved relative to each other along the long axis of apparatus 10, while preserving the fluidic connection between filter assembly 250 and fan 117. (It will be appreciated that the above-described arrangement and components represent merely one convenient way of providing a fluidic connection; any suitable fluidic connection that preserves the movability of units 20 and 60 relative to each other may be used.)

In some embodiments, one or more retaining members may be provided to retain tube 114 in position; e.g., to ensure that tube 114 does not unacceptably bow or kink when it is contracted along its long axis. In particular embodiments, such retaining members may take the form of elongate retaining fins that extend along at least a section of e.g. sleeve portion 65 and that protrude at least generally inward into the chamber within which tube 114 is positioned. Three such retaining fins are depicted in the cross- sectional cutaway view of Fig. 9; two major fins 121, and one minor fin 122 (one of the major fins 121 is also visible in Fig. 6; minor fin 122 is also visible in Fig. 13). Such fins may be positioned e.g. so that they collectively circumscribe at least a portion of the length of tube 114. By this is meant that at least one fin is present in each 120-degree segment of tube 114 (when viewed along the long axis of tube 114). As is evident in Fig. 9, it is not necessary to continuously circumferentially surround tube 114 in an uninterrupted manner for this purpose; the three-fin arrangement of Fig. 9 has been found acceptable for many circumstances.

It will be appreciated e.g. from Fig. 8 that in some embodiments air filter assembly 250 (which is directly behind the air-receiving receptacle 112 in the view of Fig. 8), hollow tube 114, and fan 117 may all be at least generally aligned with each other in a longitudinally-stacked configuration. By this is meant that these components are at least generally aligned with each other along the longitudinal axis of apparatus 10. Such an arrangement (in contrast to a design in which e.g. a fan is positioned interiorly of a filter assembly) can allow apparatus 10 to have a very small thickness dimension (that is, the dimension (Th) that extends interiorly-exteriorly, as shown in Fig. 15). It will be appreciated that this can advantageously provide that apparatus 10, when installed in an opening of a window, does not protrude very far out the window and thus will not interfere with e.g. a window screen, shutter, or the like, that might be present exteriorly of the window. This property can be characterized by means of an aspect ratio, which is defined as the ratio of the longitudinal length of the window air filter apparatus to the interior-exterior thickness of the window air filter apparatus. In various embodiments, when the movable unit is in the first, unexpanded configuration, the aspect ratio of the window air filter apparatus (measured at the point of maximum thickness of the apparatus) may be at least about 6: 1, 8: 1, 10: 1, or 12: 1.

In many embodiments, apparatus 10 may exhibit a tapered shape when viewed along the longitudinal axis of apparatus 10 (as is evident in the bottom view of Fig. 7). This may be provided by way of base unit 20 comprising first and second transverse sides 26 (provided by first and second sidewalls 38) that are tapered inwardly toward each other so that they are spaced further apart from each other at a position proximate interior side 21 of the base unit, and are spaced closer to each other at a position proximate exterior side 24 of the base unit, as shown in exemplary embodiment in Fig. 7.

Movable unit 60 may similarly comprise first and second transverse sides 66 (provided by first and second sidewalls 78) that are tapered inwardly toward each other so that they are spaced further apart from each other at a position proximate interior side 61 of the movable unit, and are spaced closer to each other at a position proximate exterior side 64 of the movable unit. Transverse sidewalls 38 and 78 of base unit 20 and movable unit 60 that establish a tapered shape in this manner, and with the sidewalls 78 of the movable unit outwardly overlying the sidewalls 38 of the base unit, are visible in the cutaway cross- sectional view of Fig. 9.

It will be appreciated that such a tapered shape of apparatus 10 can provide that when air filter apparatus 10 is installed in an opening of a sash window with the narrower end facing exteriorly and the wider end facing interiorly (as in Fig. 15), one transverse wall of apparatus 10 will abut a stationary jamb of the window, and the other transverse wall of apparatus 10 will abut an edge of the movable sash of the window, with the wide end of the tapered apparatus being on the interior side of the window opening. This arrangement can provide that apparatus 10 is less likely to be dislodged from the opening so as to fall outside of the window.

If desired, apparatus 10 may comprise one or more edge flanges that extend in a generally transverse direction, beyond the transverse edges of the main body of apparatus 10, so as to be positioned interiorly of an interior surface of e.g. the window jamb or an edge of the movable sash. Such features can additionally minimize the likelihood of apparatus 10 being dislodged so as to fall outside of the window. Thus in some embodiments, base unit 20 may comprise first and second flanges 33 that respectively extend at least generally transversely beyond the first and second transverse sidewalls 38 of the base unit, at a location proximate an interior side 21 of the base unit. Movable unit 60 may similarly comprise first and second flanges 63 that respectively extend at least generally transversely beyond the first and second transverse sidewalls 78 of the movable unit, at a location proximate interior side 61 of the movable unit. Such flanges may be e.g. made separately and attached respectively to the main bodies of the base unit and the movable unit; or, they may be integrally molded therewith. If desired, in some embodiments apparatus 10 may include one or more retaining straps with a first end that is attached to apparatus 10 and with a second end that can be attached to a retaining device (e.g., a hook) that can be mounted e.g. on an interior wall of a room, to a portion of the window frame, or the like.

Air filter apparatus 10 can be installed into an opening of a sash window, e.g. a horizontal sash window (meaning a window in which a movable sash thereof is slidably movable in a horizontal direction, e.g. as in the exemplary window 300 of Fig. 15). With reference to Fig. 15, this can be done by moving movable sash 301 (to the left, in the view of Fig. 15) to create an opening 305 in the window that is transversely wide enough to receive apparatus 10. Apparatus 10 can then be positioned in the opening, with a lowermost surface of lower end 28 of base unit 20 resting on the upward-facing surface 313 of a bottom sill 315 of the window frame 311, and with a first transverse side of apparatus 10 abutted against an inward-facing surface 312 of side jamb 317 of window frame 311. Movable unit 60 of apparatus 10 can then be moved slidably upward (along the long axis L of apparatus 10) until an uppermost surface of upper end 68 of movable unit 60 is abutted against a downward-facing surface 314 of an upper lintel 316 of window frame 311. (Apparatus 10 is self-retaining in this condition, e.g. by the use of a one-way brake as discussed later herein.) Movable sash 301 can then be slidably moved (to the right, in the view of Fig. 15) toward air filter apparatus 10 until an inward-facing face 303 of leading edge 302 of movable sash 301 is abutted against a second transverse side of air filter apparatus 10. In this manner apparatus 10 is transversely pinned in between leading edge 302 of movable sash 301 and side jamb 317; and, apparatus 10 is longitudinally pinned in between bottom sill 315 and upper lintel 316 of the window frame.

Apparatus 10 can thus be securely held in place in the opening of the window.

In some embodiments, apparatus 10 may be provided with one or more magnetic attachment elements, which can be magnetically attached to one or more complementary magnetic attachment elements that are positioned at a suitable location or locations e.g. on the window frame of the window. Such arrangements and methods are described in detail later herein.

To aid in the secure holding of apparatus 10 in place in a window opening 305, and/or to minimize any air leaks around apparatus 10, apparatus 10 can comprise resilient layers (comprised e.g. of foam rubber, or of any suitable resiliently compressible material) on various surfaces thereof. For example, a resilient layer 29 may be provided on the lower end 28 of base unit 20 e.g. so that a major surface of resilient layer 29 provides the aforementioned lowermost surface of base unit 20 that rests against the lower sill of the window frame. Similarly, a resilient layer 69 may be provided on the upper end 68 of movable unit 60 e.g. so that a major surface of resilient layer 69 provides the aforementioned uppermost surface of movable unit 60 that abuts the upper lintel of the window frame.

Resilient layers can similarly be provided on the first and second transverse sides of apparatus 10. As seen most easily e.g. in FIGs. 2 and 4, this may be achieved by way of first and second resilient layers 67 that are provided on at least portions of the first and second transverse sides 66 of movable unit 60, in combination with first and second resilient layers 27 that are provided on at least portions of the first and second transverse sides 26 of base unit 20. Such resilient layers may extend along at least a portion of the longitudinal length of the various transverse sides. In some embodiments, resilient layers 67 of movable unit 60 may each extend at least substantially along the entire longitudinal length of movable unit 60, including a portion 74 of resilient layer 67 that extends downward along sleeve portion 65 of movable unit 60, as seen in Figs. 2 and 4.

In some embodiments, resilient layers 27 of base unit 20 may each include a lowermost portion located proximate the lower end 28 of base unit 20, and also a portion 37 that extends upward along an exteriormost part of transverse side 26 of pedestal portion 36 of base unit 20, as seen in Figs. 2 and 4. Such arrangements can provide that when movable unit 60 is in the first, unexpanded condition, portion 37 of resilient layer 27 of a first transverse side 26 of base unit 20 exteriorly abuts lower portion 74 of resilient layer 67 of a first transverse side 66 of movable unit 60. Similar considerations hold for the second transverse walls of base unit 20 and movable unit 60. Such arrangements can also provide that when apparatus 10 is in an expanded condition (whether partially or fully expanded), a resilient layer may be provided at every point along the entire longitudinal length of the first and second transverse sides of apparatus 10, as is evident from Figs. 3 and 4. This can help ensure that a sufficiently air-tight seal is provided between the entire length of the first and second transverse sides of apparatus 10, and the window jamb and the leading edge of the window sash against which the first and second transverse sides are abutted, regardless of the extent to which unit 60 is expanded relative to unit 20.

Apparatus 10 may use any suitable air filter assembly 250 comprising any suitable air filter media 255 (these components are most easily visible in the interior view of Fig. 10, in which receptacle 112 has been omitted so that filter assembly 250 can be seen). In some embodiments, air filter assembly 250 may comprise an air filter media 255, e.g. a pleated air filter media as shown in Fig. 10, with a rigid support frame (not visible in Fig. 10) mounted to the perimeter thereof. Such a support frame may be made of e.g. chipboard, one or more molded plastic pieces, and so on. For ease of access, weathershield 72 may be removable from exterior side 64 of movable unit 60, at which time a filter assembly 250 may be inserted into filter assembly holder 111 (visible in Fig. 10). It will be appreciated that air-receiving receptacle 112, as discussed earlier herein and as seen in exemplary embodiment in Fig. 8, may be conveniently positioned immediately inward of filter assembly holder 111 and may be attached e.g. to holder 111 and/or to any convenient part of movable unit 60. Weathershield 72 may be reattached (e.g., by snap- fitting) to exterior side 64 of movable unit 60 to hold air filter assembly 250 securely in place. Any suitable fastener(s), clamp(s), and so on, may be used as an adjunct to, or in place of, a snap-fit attachment. In some embodiments weathershield 72 may be e.g. hingedly connected to movable unit 60 to allow access to the filter holder, rather than weathershield 72 being separable from unit 60. In some embodiments, an air filter assembly may comprise a flexible frame; or, such an assembly may be provided by a piece of air filter media alone, which may be attached to a suitable holder by any desired fastening mechanism.

Filter media 255 may be any suitable filter media, chosen from e.g. fiberglass, fibrous polymeric webs, and so on. In some embodiments, an electrostatic charge is optionally imparted into or on to material(s) of filter media 255. In other words, an electrostatically charged media may be used, of which many grades are available, and many of which offer high efficiency with low pressure drop. Thus, the filter media can be, or include, an electret nonwoven web. Electric charge can be imparted to the filter media in a variety of ways as is well known in the art, for example by hydrocharging, corona charging, etc. In other embodiments, the filter media is not electrostatically charged. Additional multi-functional media grades, which incorporate activated carbon or other materials for purifying gas-phase pollutants, may also be incorporated into a layer of the filter media. The filter media can be constructed, for example, from nonwoven fibrous media formed of thermoplastics or thermosetting materials such as

polypropylene, linear polyethylene and polyvinyl chloride. Other suitable, non-limiting materials for the filter media include porous foams, nonwovens, papers, fiberglass, or the like. In some embodiments, the filter media comprises a filter media that captures dust, allergens such as pollen and mold spores, and fine-particle pollutants, from the outdoor air. The filter media may be a single layer; or it may be a multilayer media comprised of multiple layers that serve various functions (e.g., it may include any or all of a primary particle-filtering layer, a coarse pre-filtering layer, and a gas or vapor absorbing layer). As noted, in embodiments in which apparatus 10 is a powered air filter apparatus, a fan 117 can be used to draw air in through inlet 71, through filter media 255, into and through receptacle 112, and into and through hollow tube 114. The fan also expels filtered air through outlet 31. A fan of any suitable type may be used, e.g. an axial-flow fan, a centrifugal fan, or a cross-flow fan. In particular embodiments, a centrifugal fan (often referred to as a squirrel-cage fan) may be used, with the fan comprising a long axis that coincides with the axis of rotation of the fan, which long axis is at least generally aligned with the long axis of base unit 20 in which the fan is mounted (all as shown in Fig. 8). Use of such a fan, mounted in such manner, can allow the filter, air conduit, and fan to be arranged in an a longitudinally-stacked configuration as described previously. Fan 117 can be driven by any suitable electric motor 118. In some embodiments, motor 118 and any other electrical components present, e.g. sensors, switches or the like, may be powered by an internal power source (e.g., a rechargeable battery). In other embodiments, such components may be powered by an external power cord that can enter base unit 20 e.g. through passage 35 (visible in Fig. 7).

In particular embodiments, all electrical components (including fan 117, and any on-off switches, fan speed control switches, operating circuitry, sensors, lights, indicators, and so on) of apparatus 10 may be located in base unit 20 (e.g., attached thereto, directly or indirectly). Such arrangements can provide that movable unit 60 need not include any electrical component of any kind, which can simplify the manufacture and operation of apparatus 10.

In some embodiments, fan 117 can be mounted in a fan chamber 116 that is defined within lower, pedestal portion 36 of base unit 20. A ceiling of such a fan chamber can be provided e.g. by partition 115 as shown in Fig. 8. In particular embodiments, partition 115 may be an at least generally horizontally- extending partition, to which various components of apparatus 10 may be conveniently attached as discussed later herein. Regardless of the particular design, partition 115 may comprise a through-passage through which air that is received from hollow tube 114 (which tube may be fluidically connected to partition 115 by way of e.g. any suitable fitting) can enter fan chamber 116.

It will be appreciated that the tolerances with which various components of apparatus 10 are abutted near each other and/or attached to each other may be controlled so as to minimize the number and/or amount of air leaks into apparatus 10. This may advantageously provide that little or no exterior air is able to bypass filter media 255 so as to e.g. allow unfiltered air to enter a building through apparatus 10. Such arrangements may also maximize the efficiency of power use (e.g., by minimizing the amount of room air that may enter fan chamber 116 and be inadvertently recirculated).

It will be appreciated that such tight-fitting of various components to minimize air leaks must nevertheless preserve the ability to move units 60 and 20 back and forth relative to each other as previously described. In particular, the closeness with which the various walls (e.g., transverse walls, interior walls, and exterior walls) of base unit 20 and movable unit 60 approach each other can be controlled to provide a tight fit in at least portions of these units, as is evident in e.g. Fig. 9. (Fig. 9 also shows an exemplary arrangement of the various walls of units 20 and 60 that allow the units to be slidably moved relative to each other without coming apart from each other.) If desired, resilient layers (e.g., foam weatherstripping) can be provided e.g. between surfaces of base unit 20 and movable unit 60 at locations most advantageous to minimize air leaks. It will also be appreciated that the presence of partition 115 that provides a ceiling of fan chamber 116 (and also the use of close-fit tolerances on any items that pass through partition 115, e.g. a sliding bar as described later herein) can help ensure that even if unfiltered air is able to enter an upper portion of apparatus 10, such air may not be able to easily enter fan chamber 116.

As noted, in the installation of apparatus 10 into an opening of a window, apparatus 10 is placed into the opening e.g. with the lower end of base unit 20 resting on the window sill, and movable unit 60 is moved slidably upward until the upper end of movable unit 60 is abutted against the window lintel. In many embodiments, it may be useful for apparatus 10 to include a one-way brake 150 that allows movable unit 60 to be self-retaining in such a configuration, to render the installation easier for a user. Such a one-way brake may comprise a first, engaged configuration, in which engaged configuration the brake allows movable unit 60 to move away from the first, unexpanded configuration toward the second, expanded configuration. However, in the first, engaged configuration the brake prevents the movable unit from moving away from the second, expanded configuration toward the first, unexpanded configuration. With reference to Fig. 15, such a one-way brake can allow movable unit 60 to be moved upward as desired; and, unit 60 can then be left at any desired position without it being impelled by gravity to slidably move back downward. In particular embodiments, this engaged configuration is a default configuration of brake 150, meaning that the brake is always in the engaged configuration unless a user acts to remove the brake from the engaged configuration and to actively keep the brake from returning to an engaged configuration. This can provide that a user does not have to perform any action (e.g., pushing a button, turning a lever, etc.) to release the brake in order to slidably move unit 60 upward. Nor does a user have to continuously, or intermittently, perform any such action during the process of slidably moving unit 60 upward.

In at least some embodiments, brake 150 can be actuated (e.g., manually, by a user) into a second, disengaged configuration that allows movable unit 60 to be moved reversibly back and forth (e.g., up and down) in either direction between the first, unexpanded configuration and the second, expanded configuration. Thus, brake 150 can be actuated into the second, disengaged configuration when it is desired to put apparatus 10 into an unexpanded condition (e.g., so that apparatus 10 can be more easily removed from a window). In embodiments in which the engaged configuration of brake 150 is a default configuration, the actuation must be maintained to keep the brake disengaged in order to keep moving unit 60 toward the first, unexpanded configuration. That is, if the actuation is performed e.g. by pushing a button, the user must keep the button pushed in order to keep moving unit 60 toward an unexpanded configuration. Brake 150 can take the form of any braking device or mechanism that can perform the above- described one-way braking when engaged, and can allow bidirectional motion when disengaged. In various embodiments, such one-way braking devices may rely on e.g. ratchets, cog wheels, and so on. However, in some embodiments, brake 150 is a non-stepwise brake, meaning that brake 150 is configured so that when the brake is in the engaged configuration the brake allows movable unit 60 to be moved away from the first, unexpanded configuration toward the second, expanded configuration, in a continuous manner (e.g. any desired amount, e.g. a fraction of a millimeter) rather than in stepwise increments. (Such a brake will also, when disengaged, allow continuous rather than stepwise motion, in either direction.)

Any suitable one-way, non-stepwise brake can be used as desired. In some embodiments, such a brake may rely on one or more cams each comprising a protrusion that when in a first, engaged configuration, frictionally impinges on a bar at an angle so as to allow motion in one direction but not in the opposite direction. The one or more cams can be rotated to a second, disengaged configuration in which the cam protrusion is spaced away from the bar so as to allow movement in either direction. Oneway, non-stepwise brakes of this general type are described in U.S. Provisional Patent Application No. xx/xxxxxx, attorney docket number 76771US002, entitled Unpowered Window Air Filter Apparatus, filed evendate herewith, which is incorporated by reference herein in its entirety. In other embodiments, such a one-way, non-stepwise brake may rely on braking member that, when in a first, engaged configuration, frictionally impinges on a slider bar so as to allow motion in one direction but not in the opposite direction. The braking member can be actuated to a second, disengaged configuration in which it allows movement in either direction. One-way, non-stepwise brakes of this general type are described in described in U.S. Provisional Patent Application No. xx/xxxxxx, attorney docket number 76687US002, entitled Powered Window Air Filter Apparatus, filed evendate herewith, which is incorporated by reference herein in its entirety. Any brake of any such type can be actuated by any suitable actuator, e.g. a push-button, a handle to be turned or pulled, and so on.

As discussed above, in at least some embodiments movable unit 60 of apparatus 10 can be moved toward an expanded configuration, e.g. upward, and a one-way brake 150 can provide that movable unit 60 will not move back downward to any appreciable extent (even if the user lets go of movable unit 60) unless the brake is disengaged. When the brake is disengaged, movable unit 60 can then be moved downward (or allowed to move downward under the influence of gravity). In some embodiments, it may be advantageous for apparatus 10 to comprise a one-way speed limiter 160 that limits the speed at which movable unit 60 can be moved away from the second, expanded configuration toward the first, unexpanded configuration (such movement, in most uses of apparatus 10, will correspond to a downward direction relative to the Earth). However, limiter 160 will not appreciably limit the speed at which movable unit 60 can be moved away from the first, unexpanded configuration toward the second, expanded configuration (such a movement, in most uses of apparatus 10, will correspond to an upward direction). Limiter 160 can be of any suitable design, operating by any suitable mechanism of action. One exemplary type of limiter 160 is described in detail in U.S. Provisional Patent Application No.

xx/xxxxxx, attorney docket number 76687US002, entitled Powered Window Air Filter Apparatus, filed evendate herewith, which is incorporated by reference herein in its entirety.

Regardless of the specific configuration and components, such arrangements can provide that when the one-way brake is actuated to disengage the brake to allow movable unit 60 to move downward, away toward an unexpanded configuration, the limiter can ensure that the Earth's gravity does not cause unit 60 to move downward too rapidly. It will thus be appreciated that the arrangements disclosed herein can allow a user to grasp base unit 20 (e.g. by grasping either lower handle 22 or upper handle 23), and to push actuator button 34. This can allow movable unit 60 to gently descend, motivated by gravity but with the speed limited by limiter 160, without the user necessarily having to grasp any portion of movable unit 60 during this process. (To raise unit 60 to an expanded condition, a user can of course grasp handle 22 or 23 of base unit 20 with one hand, and grasp handle 62 of movable unit 60 with the other hand to raise unit 60, since it is not necessary to push actuator button 34 in order to move unit 60 in this direction.)

If desired, apparatus 10 may include a scent element that can be inserted at any convenient point along the air pathway from inlet 71 to outlet 31. The moving air may impinge on the scent element (e.g., the air may pass through it, if the scent element is e.g. a fibrous web that is loaded with a scent) so as to volatilize any scent therein. (The term scent is used broadly, to encompass e.g. any fragrance, essential oil, and so on, that a user may desire to have broadcast into e.g. a living space.) In some embodiments, a scent element may be a fibrous web as noted, which web may be insertable into the air pathway e.g. through an entry slot. Or a scent element may be provided by way of having a receptacle or pathway into which a liquid scent (e.g., an essential oil) can be placed (e.g., with a dropper) and from which it is able to follow a flowpath into the air pathway.

If desired, a piece (e.g., an elongate length) of resilient material (e.g. foam rubber,

weatherstripping, or the like) can be inserted in between the glass of the movable sash 301, and the glass of the other (e.g., non-movable) sash 304, e.g. at location 318 of Fig. 15, in order to minimize any passage of unfiltered air through the small gap between these glass layers that may result from the window being (partly) open.

Also if desired, a window-stop may be positioned e.g. at location 319 of Fig. 15. Such a window- stop may ensure that movable sash 301 is not inadvertently moved (leftward, in the view of Fig. 15) away from its position of being abutted against a lateral side of apparatus 10. Such a window-stop may be any suitable item, e.g. a rubber wedge whose leading edge may be jammed against the trailing edge of movable sash 301, an elongate rod with one end abutted against the trailing edge of movable sash 301 and the other end abutted against the side jamb of the window frame, and so on. Either or both of such a piece or pieces of e.g. weatherstripping, and a window-stop, may be included in a kit that e.g. comprises an apparatus 10 (which may already have one filter assembly 250 installed therein) and that comprises one or more replacement filter assemblies, instructions for use, and so on.

Although discussions herein have focused on sash windows with e.g. one horizontally movable sash and with one sash that is fixed in place, it will be appreciated that apparatus 10 may easily be installed in a window that comprises two horizontally movable sashes (in such case, either sash may be chosen to be moved so as to provide a window opening in which to install apparatus 10). Moreover, although discussions herein have focused on horizontal sash windows (meaning windows with at least one movable sash that is movable in a direction that is at least generally horizontal with respect to the Earth), it will be appreciated that apparatus 10 may be easily installed in a vertical sash window (meaning a window with at least one movable sash that is movable in a direction that is at least generally vertical with respect to the Earth). In such a case, the movable sash may be moved e.g. upward to provide an opening with a vertical span sufficient to accommodate the transverse direction (the width) of apparatus 10. Apparatus 10 may then be positioned so that the "lower" end 28 of apparatus 10 abuts a first jamb of the window, and so that the "upper" end 68 of apparatus 10 abuts a second jamb of the window, and with one transverse side of apparatus 10 resting on the window sill. After this, the vertically-movable sash can then be moved downward so that its leading edge is abutted against the other transverse side of apparatus 10. (Apparatus 10 could also be installed in an opening in the upper part of a vertical sash window, rather than in an opening in the lower part.)

It will thus be appreciated that installation and use of apparatus 10 in a vertical sash window can be performed in the same manner as described herein with regard to a horizontal sash window, with apparatus 10 merely being rotated e.g. 90 degrees with respect to the Earth. It will thus be understood that the use herein of terms such as upper, lower, above, below, uppermost, lowermost, and so on, are used for convenience of description in the exemplary embodiment of installation of apparatus 10 in a horizontal sash window; it is emphasized that such language does not limit the use of apparatus 10 to horizontal sash windows.

In some embodiments, window air filter apparatus 10 may be convertible into a room air purifier (RAP). In such use, apparatus 10 will draw in room air, filter it, and recirculate it into the room, rather than drawing in outside air to be filtered and emitted into a room.

Magnetically attachable window air filter

In some embodiments, a window air filter apparatus 10 may be magnetically installable in a window. In this context, by install, installable and like terms is meant that apparatus 10 may be magnetically attached to a window frame so that e.g. at least a substantial portion of apparatus 10 resides in the opening of the window. However, such terms also encompass positioning apparatus 10 so that at least a substantial portion of apparatus 10 resides interiorly proximate the window opening. An exemplary apparatus 10, installed in a window 300, is shown in idealized representation in Fig. 11 (in the arrangement of Fig. 11, essentially the entirety of apparatus 10 resides interiorly proximate opening 305 of window 300). In some embodiments, apparatus 10 comprises at least one magnetic attachment element 601, that is magnetically attachable to a complementary magnetic attachment element 602 that is bonded to some portion of a window frame 311. The term magnetic attachment element encompasses elements that are permanent magnets (e.g., made of a magnetized material such as iron, nickel, cobalt, or alloys such as permalloy, alnico and the like). The term magnetic attachment element also encompasses materials that are ferromagnetic (and thus will be attracted to a permanent magnet) but are not themselves magnetized so as to be a permanent magnet. Such materials may be made of e.g. iron, certain steels, cobalt, and various alloys.

In some embodiments, both a magnetic attachment element 601 of apparatus 10 and a complementary magnetic attachment element 602 of window frame 311 may be permanent magnets. In other embodiments, element 601 may be a permanent magnet and element 602 may be a ferromagnetic material that is not permanently magnetized. In still other embodiments, the reverse may be true.

Magnetic attachment element 601 may be bonded (fastened) to any suitable portion of apparatus 10, e.g. to a surface thereof, by any suitable bonding mechanism. Such a mechanism may be e.g. one or more pieces of double-faced pressure-sensitive adhesive, or a liquid glue or adhesive (whether e.g.

thermally curable, moisture-curable, light-curable, and so on). Or, such a bonding mechanism may take the form of one or more screws, nails, clips, clamps, or the like. A complementary magnetic attachment element 602 may likewise be bonded to any suitable portion of window frame 311, by any suitable bonding mechanism including any of those just mentioned. In the exemplary embodiment of Fig. 11, element 602 is bonded to interior face 321 of upper lintel 316 of window frame 311, by a layer of double- faced pressure-sensitive adhesive 605. Element 602 and element 601 may be, but do not have to be, bonded respectively to apparatus 10 and to window frame 311 by the same bonding mechanism.

In specific embodiments, magnetic attachment element 601 of apparatus 10 is a permanent magnet and complementary magnetic attachment element 602 of window frame 311 is an unmagnetized ferromagnetic material, e.g. a steel plate of composition chosen so as to exhibit ferromagnetic properties. Such embodiments include the special case in which at least some portion of window frame 311 (e.g., upper lintel 316) is itself made of a ferromagnetic material; in such cases this portion of the window frame can serve as the complementary magnetic attachment element 602 to which magnetic attachment element 601 of apparatus 10 is magnetically attached.

In some embodiments apparatus 10 may include only a single magnetic attachment element, which might be located at an upper end (as for element 601 of Fig. 11) or at a lower end (as for element 603 of Fig. 11) of apparatus 10. In other embodiments apparatus 10 may include at least one magnetic attachment element 601 at an upper end of apparatus 10, and at least one magnetic attachment element 603 at a lower end of apparatus 10. Such attachment elements may be of any suitable shape and size, and number, and, as noted, can be bonded to any suitable location, surface, or component of apparatus 10. In some embodiments, at least one magnetic attachment element may be bonded to an interior side 61 (e.g., to a major surface of side 61) of movable unit 60 of apparatus 10, as in the exemplary embodiment of Fig. 11. Likewise, at least one magnetic attachment element may be bonded to an interior side 21 (e.g., to a major surface thereof) of base unit 20 of apparatus 10, again as depicted in exemplary manner in Fig. 11. It will be appreciated that such arrangements may provide that at least a major portion, or the entirety, of apparatus 10 is positioned interiorly of opening 305 of window 300, e.g. in the general manner depicted in Fig. 11. Thus in such embodiments the main body of apparatus 10 may not necessarily extend into opening 305.

In other embodiments, magnetic attachment elements can be positioned so that at least a significant, or substantial, portion of the main body of apparatus 10 can be positioned within window opening 305 if desired. Such arrangements may enhance the ability of apparatus 10 to be vertically and transversely pinned in place in window opening 305, as discussed previously. Such arrangements may combine with the magnetic attachment(s) to enhance the stability with which apparatus 10 is held in place in opening 10. One exemplary design that allows such functioning is shown in side view in Fig. 12 and in interior perspective view in Fig. 13. In such cases, magnetic attachment element 601 is bonded to a flange 79 that extends upwardly from upper end 68 of movable unit 60, at a location proximate the interior side of unit 60. Magnetic attachment element 603 is similarly bonded to a flange 39 that extends downwardly from lower end 28 of base unit 20, at a location proximate the interior side of unit 20. Attachment elements 601 and 603 can be respectively magnetically attached to complementary magnetic attachment elements 602 and 604 that are respectively positioned on (e.g. bonded to) interior face 321 of window frame lintel 316, and on interior face 322 of window frame sill 315. As is evident from the exemplary depiction of Fig. 12, such arrangements allow the main body of apparatus 10 to be positioned at least partially, or substantially, within opening 305, in the general manner described earlier herein.

In various embodiments, such a flange (and at least one associated magnetic attachment element) may be provided only at the upper end of apparatus 10 (in the manner of flange 79), or only at the lower end of apparatus 10 (in the manner of flange 39). Or, flanges may be provided at both ends of apparatus 10, as in the design of Figs. 12 and 13. A single magnetic attachment element may be provided on a flange (as exemplified by attachment element 601 that is on flange 79, and attachment element 603 that is on flange 39). If desired, such a single magnetic attachment element may take the shape of an elongated bar with a long axis that is at least generally aligned with the transverse direction of apparatus 10. In other embodiments, multiple magnetic attachment elements may be provided on a flange, e.g. spaced across a long axis thereof. Such an attachment element or elements may be bonded to a flange (e.g. to an exterior face thereof) by any suitable bonding mechanism, e.g. by any of the bonding mechanisms described previously. Rather than a single flange that extends across e.g. the entire transverse width of apparatus 10, if desired multiple flanges (each with at least one magnetic attachment element) can be provided; for example, flange 79 could be replaced by e.g. two smaller flanges, each at one transverse corner of upper end 68 of apparatus 10. As noted, a complementary magnetic attachment element (e.g., element 602 or element 604 of Fig. 11) can be bonded to any portion of frame 311 by any suitable bonding mechanism. In at least some embodiments it may be convenient to perform this bonding by use of a double-faced pressure-sensitive adhesive 605. Such an approach can allow a complementary magnetic attachment element 602 that is to be bonded to a window frame, to be pre-attached to magnetic attachment element 601 of apparatus 10 (specifically, an interior face of element 602 is magnetically attached to an exterior face of element 601). A layer of double-faced pressure-sensitive adhesive 605 is bonded to the exterior face of element 602 (element 602 may come with a piece of adhesive pre-bonded thereto; or, the bonding of adhesive 605 to element 602 may be performed by a user). Apparatus 10 can then be inserted into place in a window opening 305, e.g. with the upper end of apparatus 10 tilted slightly interiorly to minimize the change of premature contact of pressure -sensitive adhesive 605 with window frame 311. Apparatus 10 can then be gradually rotated so that its upper end moves exteriorly toward lintel 316; as this is performed, movable unit 60 of apparatus 10 can be slidably moved up or down as needed to position unit 60 so that e.g. a resilient layer 69 positioned on upper end 68 thereof, comes in contact with downward-facing surface 314 of window lintel 316. With unit 60 positioned at an optimal up-down location in this manner, apparatus 10 can then be rotated to a final position in which an exterior face of double-faced pressure-sensitive adhesive 605 (any liner having been previously removed therefrom) comes into contact with interior face 321 of window lintel 316 and bonds thereto. (Apparatus 10 can then be left in place at least momentarily to ensure adequate bonding of adhesive 605 to lintel face 321.) It will be appreciated that such arrangements can provide that double-faced pressure-sensitive adhesive 605 (and thus magnetic attachment element 602) is positioned in an appropriate location on lintel 316. In some embodiments, such an approach may only be used for one of magnetic attachment elements 602 and 604. In other embodiments, such an approach may be used for both magnetic attachment elements 602 and 604.

In other embodiments, a magnetic attachment element may be bonded to a portion of a window frame (whether by way of a double-faced adhesive, or by any other bonding mechanism) prior to the insertion of apparatus 10 in position in the window. A user may of course temporarily position apparatus 10 in the window prior to attaching the magnetic attachment element to the window frame, in order to ascertain a suitable location to place the magnetic attachment element.

It may not be necessary that a magnetic attachment element (e.g., element 601) of apparatus 10, and a complementary magnetic attachment element (e.g. element 602) that is positioned on window frame 311, be of the exact same size and/or shape. Nor must they be aligned exactly with each other (e.g., so that their perimeters coincide exactly) to perform the desired magnetic attachment. All that is needed is for sufficient overlap to be present to achieve an adequate attractive magnetic force therebetween. In fact, in some embodiments it may be advantageous for one of the magnetic attachment elements (e.g. an element positioned on window frame 311) to be larger in size (area) than the magnetic attachment element of apparatus 10. This may enhance the ability to perform the desired attachment, without requiring a user to meticulously align the magnetic attachment elements with each other in an exact manner.

In some embodiments, a flange (e.g., flange 79) that extends upwardly from upper end 68 of apparatus 10 may be configured so that it can also serve as a hanger (instead of being used for magnetic attachment) e.g. in the event that apparatus 10 is desired to be used as a powered room air purifier rather than being installed in a window. For example, flange 79 may include a through-hole that allows apparatus 10 to be hung from a hook or any similar apparatus.

One or more flanges (e.g. flanges 39 and 79 of Figs. 12 and 13) can be provided as part of base unit 20 or of movable unit 60, in any suitable way. In some embodiments, such a flange or flanges may be a separately made piece that is attached to a main body of base unit 20 or movable unit 60. In other embodiments, such a flange or flanges may be integral with unit 20 or unit 60; i.e. it may be a portion of unit 20 or 60 that is molded along with e.g. the main body (and possibly other components) of unit 20 or 60. In some embodiments a flange may be pivotally (e.g., hingedly) connected to a main body of unit 20 or 60. This can allow that e.g. if magnetic attachment is not needed, a flange can be rotatably moved so as to not interfere with the ability to insert apparatus 10 into a window opening. For example, flange 79 as shown in Figs. 12 and 13 could be hingedly connected to unit 60 at the bottom of flange 79, and flange 79 could then be rotated so that the upper end of flange 79 moves interiorly and downwardly. Similar arrangements (although oriented oppositely) can be made for flange 39 of unit 20. In some embodiments, such a flange or flanges may be a separately made piece that is then hingedly connected to some portion of apparatus 10. In embodiments, in which a flange is integral with unit 20 or with unit 60, such a flange may be molded so as to be connected to e.g. the main body of unit 20 or unit 60, by way of a living hinge.

In embodiments in which a flange 79 is not integral with movable unit 60, such a flange can be slidably connected to unit 60 (e.g., to an upper end 68 thereof) so that the flange can be slidably moved back and forth at least generally along an interior-exterior direction of unit 60. Flange 39 can be arranged in similar manner relative to base unit 20. Such arrangements can allow the flanges to be positioned so that the desired magnetic attachment of apparatus 10 to the window frame is achieved, while also allowing apparatus 10 to be positioned (along an interior-exterior direction) for optimum placement of the transverse sides and top and bottom of apparatus 10, respectively against surfaces of the window side jamb, the leading edge of the movable sash, the window lintel, and the window sill.

If desired, one or more magnetic attachment elements may also be provided (e.g., on a flange that extends at least generally transversely from the main body of apparatus 10) that are magnetically attachable to at least one complementary magnetic attachment element that is bonded e.g. to a side jamb 317 of window frame 311. Such a flange or flanges may be produced and arranged in generally similar manner to those described above.

In some embodiments, apparatus 10 may include at least one magnetic attachment element that is positioned on an upward-facing surface of upper end 68 of apparatus 10 or is positioned on a downward- facing surface of lower end 28 of apparatus 10. In some embodiments, such an attachment element or elements may be present in addition to the previously-described magnetic attachment elements that are positioned on an exterior-facing surface of apparatus 10. In other embodiments, such an attachment element or elements may be the only magnetic attachment elements present. Fig. 14 shows an exemplary design in which at least one magnetic attachment element 601 is provided on the upward-facing surface of upper end 68 of apparatus 10, and can be magnetically attached to a complementary magnetic attachment element 602 that is bonded to downward-facing surface 314 of upper lintel 316 of window frame 311. In the depicted design, at least one additional magnetic attachment element 603 is provided on the downward-facing surface of lower end 28 of apparatus 10, that can be magnetically attached to a complementary magnetic attachment element 604 that is bonded to upward-facing surface 313 of lower sill 315 of window frame 311. Although not shown in Fig. 14, in some embodiments the thickness (in the up-down direction) of an upper magnetic attachment element 601 of apparatus 10 may be chosen in relation to the thickness of a resilient layer (e.g., a foam pad) 69 that is also provided on upward-facing surface of upper end 68 of apparatus 10. For example, the initial (while not under any compressive force) thickness of such a resilient layer may be chosen in combination with the compressibility of the resilient layer so that the resilient layer allows the magnetic attachment to be performed but so that at least some area of the upper surface of the resilient layer nevertheless contacts the downward-facing surface of the window lintel so as to seal against air leaks. Similar arrangements can be made for a resilient layer 29 provided on the lower-facing surface of lower end 28 of apparatus 10.

Although the descriptions herein have focused primarily on powered air filter apparatus, the magnetic attachment devices and methods disclosed herein may also be used with an unpowered (e.g., passive) air filter apparatus that is to be installed in a window opening and that may similarly use a first, base unit and a second, movable unit that is slidably movable relative to the first, base unit. Such apparatus are described in detail in U.S. Provisional Patent Application Serial No. xx/xxxxxx, attorney docket number 76671US002, filed evendate herein with and entitled Unpowered Window Air Filter Apparatus, the entirety of which is incorporated by reference herein. Although the descriptions herein have focused primarily on window air filter apparatus, the magnetic attachment devices and methods disclosed herein may be used with a window air filter apparatus that can also be used as a powered room air purifier. Such apparatus are described in detail in U.S. Provisional Patent Application Serial No. xx/xxxxxx, attorney docket number 76395US002, filed evendate herein with and entitled Dual-Mode Air Filter Apparatus, the entirety of which is incorporated by reference herein.

List of Exemplary Embodiments

Embodiment 1 is a window air filter apparatus, comprising: a first, base unit; and, a second, movable unit; wherein the second, movable unit is reversibly slidably movable back and forth relative to the first, base unit, between at least a first, unexpanded configuration and a second, expanded

configuration, wherein the first, base unit includes at least one first magnetic attachment element that is bonded to a lower, pedestal portion of the first, base unit and that is magnetically attachable to at least one first complementary magnetic attachment element that is bonded to a portion of a frame of a sash window, and wherein the second, movable unit includes at least one second magnetic attachment element that is bonded to an upper, shroud portion of the second, movable unit and that is magnetically attachable to at least one second complementary magnetic attachment element that is bonded to a portion of the frame of the sash window.

Embodiment 2 is the window air filter apparatus of embodiment 1 wherein the window air filter apparatus is a powered window air filter apparatus in which the first, base unit comprises a fan and the second, movable unit comprises an air filter; and, wherein the fan and the air filter are fluidically connected to each other by a conduit that includes at least one reversibly expandable and contractible section and that allows the second, movable unit to be reversibly slidably moved back and forth between the first, unexpanded configuration and the second, expanded configuration while maintaining the fluidic connection between the fan and the air filter.

Embodiment 3 is the window air filter apparatus of any of embodiments 1-2 wherein the window air filter apparatus is an unpowered window air filter apparatus that includes a pleated air filter media with a first uncorrugated end that is attached to the first, base unit and with a second corrugated end that is attached to the second, movable unit; and, wherein the pleated air filter media is reversibly extendable and collapsible between a first, unexpanded configuration and a second, expanded configuration so as to allow the second, movable unit of the apparatus to be reversibly slidably movable back and forth relative to the first, base unit between at least the first, unexpanded configuration and the second, expanded configuration.

Embodiment 4 is the window air filter apparatus of any of embodiments 1-3 wherein the at least one first magnetic attachment element faces exteriorly from an exterior side of the lower, pedestal portion of the first, base unit, at a location that is proximate a lower end of the pedestal portion of the first, base unit, and wherein the at least one second magnetic attachment unit faces exteriorly from an exterior side of the upper, shroud portion of the second, movable unit, at a location that is proximate an upper end of the shroud portion of the second, movable unit.

Embodiment 5 is the window air filter apparatus of any of embodiments 1-4 wherein the at least one first magnetic attachment element is bonded to a first flange that extends at least generally downward from the lower, pedestal portion of the first, base unit beyond a lower end of the lower, pedestal portion of the first base unit; and, wherein the at least one second magnetic attachment element is bonded to an exterior face of a second flange that extends at least generally upward from the upper, shroud portion of the second, movable unit beyond an upper end of the upper, shroud portion of the second base unit. Embodiment 6 is the window air filter apparatus of embodiment 5 wherein the first flange is integral with the lower, pedestal portion of the first, base unit, and wherein the second flange is integral with the upper, shroud portion of the second, movable unit. Embodiment 7 is the window air filter apparatus of embodiment 5 wherein the first flange is a separately made piece that is attached to the lower, pedestal portion of the first, base unit, and wherein the second flange is another separately made piece that is attached to the upper, shroud portion of the second, movable unit. Embodiment 8 is the window air filter apparatus of any of embodiments 5-7 wherein the first flange is movably attached to the lower, pedestal portion of the first unit, and wherein the second flange is movably attached to the upper, shroud portion of the second, movable unit. Embodiment 9 is the window air filter apparatus of embodiment 8 wherein the first flange is rotatably attached to the lower, pedestal portion of the first unit and is configured so that the first flange can be rotated interiorly and upwardly away from a configuration in which the first flange extends beyond a lower end of the lower, pedestal portion of the first base unit; and, wherein the second flange is rotatably attached to the upper, shroud portion of the second, movable unit and is configured so that the second flange can be rotated interiorly and downwardly away from a configuration in which the first flange extends beyond an upper end of the upper, shroud portion of the second, movable unit.

Embodiment 10 is the window air filter apparatus of any of embodiments 5-9 wherein the window air filter apparatus is a powered filter apparatus in which the first, base unit comprises a fan and the second, movable unit comprises an air filter, and wherein the second flange comprises at least one feature that allows the second flange to serve as a hanger by way of which the powered air filter apparatus can be hung from a supporting structure within the interior of a room of a building so that the powered air filter can serve as a powered room air purifier.

Embodiment 11 is the window air filter apparatus of any of embodiments 1-10 wherein the window air filter apparatus is a powered filter apparatus in which the first, base unit comprises a fan and the second, movable unit comprises an air filter, wherein the fan and the air filter are fluidically connected to each other by a conduit that includes at least one reversibly expandable and contractible section and that allows the second, movable unit to be reversibly slidably moved back and forth between the first, unexpanded configuration and the second, expanded configuration while maintaining the fluidic connection between the fan and the air filter. Embodiment 12 is the window air filter apparatus of any of embodiments 1-11, wherein the base unit and the movable unit each exhibit a longitudinal axis and a transverse axis, wherein the longitudinal axis of the base unit and the longitudinal axis of the movable unit are aligned with each other so as to define a longitudinal axis of the powered air filter apparatus, and wherein the direction along which the movable unit is reversibly slidably movable is aligned with the longitudinal axis of the powered air filter apparatus. Embodiment 13 is the window air filter apparatus of any of embodiments 1-12 wherein the base unit and the movable unit each comprise first and second transverse walls that are tapered inwardly toward each other so that they are spaced further apart from each other at a position proximate an interior wall of the unit, and are spaced closer to each other at a position proximate an exterior wall of the unit. Embodiment 14 is the window air filter apparatus of embodiment 13 wherein the first and second transverse walls of the base unit each comprise a generally transversely -outwardly-facing resilient layer along at least a portion of a longitudinal length of the transverse wall, and wherein the first and second transverse walls of the movable unit each comprise a generally transversely-outwardly-facing resilient layer along at least a portion of a longitudinal length of the transverse wall; and, wherein when the movable unit is in the first, unexpanded condition, at least a portion of the resilient layer of the first transverse wall of the base unit exteriorly abuts a lower portion of the resilient layer of the first transverse wall of the movable unit, and at least a portion of the resilient layer of the second transverse wall of the base unit exteriorly abuts a lowermost portion of the resilient layer of the second transverse wall of the movable unit.

Embodiment 15 is a kit comprising the window air filter apparatus of any of embodiments 1-14 and at least one first complementary magnetic attachment element that is configured to be bonded to a window frame, and at least one second complementary attachment element that is configured to be bonded to a window frame. Embodiment 16 is the kit of embodiment 15 wherein the kit includes at least one first piece of double-faced pressure-sensitive adhesive that is configured to bond the first

complementary magnetic attachment element to an interior surface of a window frame, and includes at least one second piece of double-faced pressure-sensitive adhesive that is configured to bond the second complementary magnetic attachment element to an interior surface of the window frame.

Embodiment 17 is a method of installing a window air filter apparatus in a window, the method comprising: providing a window air filter apparatus that comprises a first, base unit and a second, movable unit; wherein the second, movable unit is reversibly slidably movable back and forth relative to the first, base unit, between at least a first, unexpanded configuration and a second, expanded

configuration, and wherein the first, base unit includes at least one first magnetic attachment element that is bonded to a lower, pedestal portion of the first, base unit and wherein the second, movable unit includes at least one second magnetic attachment element that is bonded to an upper, shroud portion of the second, movable unit; inserting the apparatus into a sash window so that the at least one first magnetic attachment element is brought into contact with, and is magnetically attached to, at least one first complementary magnetic attachment element that is bonded to a portion of a frame of the window; and so that the at least one second magnetic attachment element is brought into contact with, and is magnetically attached to, at least one second complementary magnetic attachment element that is bonded to a portion of a frame of the window.

Embodiment 18 is the method of embodiment 17 wherein the at least one first complementary magnetic attachment element is bonded to a lower sill of the window frame and wherein the at least one second complementary magnetic attachment element is bonded to an upper lintel of the window frame. Embodiment 19 is the method of embodiment 18 wherein the at least one first complementary magnetic attachment element is pressure-sensitive adhesively bonded to an upward-facing surface of the lower sill of the window frame and wherein the at least one second complementary magnetic attachment element is pressure-sensitive adhesively bonded to a downward-facing surface of the upper lintel of the window frame. Embodiment 18 is the method of claim 17 wherein the method is carried out with the window air filter apparatus of any of embodiments 1-14.

It will be apparent to those skilled in the art that the specific exemplary elements, structures, features, details, configurations, etc., that are disclosed herein can be modified and/or combined in numerous embodiments. All such variations and combinations are contemplated by the inventor as being within the bounds of the conceived invention, not merely those representative designs that were chosen to serve as exemplary illustrations. Thus, the scope of the present invention should not be limited to the specific illustrative structures described herein, but rather extends at least to the structures described by the language of the claims, and the equivalents of those structures. Any of the elements that are positively recited in this specification as alternatives may be explicitly included in the claims or excluded from the claims, in any combination as desired. Any of the elements or combinations of elements that are recited in this specification in open-ended language (e.g., comprise and derivatives thereof), are considered to additionally be recited in closed-ended language (e.g., consist and derivatives thereof) and in partially closed-ended language (e.g., consist essentially, and derivatives thereof). To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document incorporated by reference herein, this specification as written will control.