Patent Description:
Systems utilizing fluid during operation, such as modern internal combustion engine systems, often include fluid filters to ensure proper or reliable performance. For example, internal combustion engine systems may include air cleaners containing an air filter to remove dirt and other particulates from engine intake air before combustion. As a consequence of their proper operation, these filters collect particulates over time and increasingly restrict the flow of air or fuel into engines. Eventually, the filters may become more restrictive than desirable for fuel efficiency or other performance criteria and may require replacement.

To facilitate timely filter replacement, some systems include filter monitoring devices to provide an indication of the filter restriction to users. For example, a restriction indicator may monitor levels of vacuum pressure that result from air flow through the associated filter in the air cleaner. The restriction indicator may be calibrated to detect when particular vacuum pressure levels occur and provide an indication of the level. Some restriction indicators provide a visible indication of the restriction.

Restriction indicators can be difficult to install or service. Some restriction indicators are removably coupled to a housing of the air cleaner by a threaded connection, which requires precise alignment of threads to function properly and multiple turns. Some indicators are coupled by a quick-connect fitting, which may easier to install or remove than a threaded connection but may protrude far from the housing of the air cleaner to accommodate the quick-connect mechanism and be more easily damaged. Other indicators may require an adaptor to fit onto the housing of the air cleaner. Furthermore, restriction indicators may be difficult for users to see, at times, due to their placement on the air cleaner housing and limited functionality. Document <CIT> discloses a display device for indicating the degree of contamination of an air filter element. Document <CIT> discloses an apparatus for diagnosing a deteriorated automotive internal combustion engine intake air filter. Document <CIT> discloses a hand-held portable vacuum comprising a filter indicator to indicate that replacement or cleaning of the filter is required.

There remains a need for improved visual restriction indicators having connection features that facilitate the ease of installation and service, as well as improved visibility for users. An air cleaner assembly according to the invention is disclosed in the appended claims <NUM>-<NUM>.

Various aspects of the present disclosure relate to air cleaner assemblies with a removable restriction indicator. In one or more embodiments, the removable restriction indicator is mounted to a receptacle on a housing of an air cleaner in a manner that is easy to install and service. The restriction indicator may be installed by inserting a portion of the restriction indicator into the receptacle of the air cleaner housing. During installation of one or more embodiments of the restriction indicator as described herein, a stem of the restriction indicator may be inserted into a bore of the air cleaner housing and sealed thereto, and one or more tabs of the restriction indicator may engage a corresponding aperture to secure the restriction indicator to the housing. When mounted, the restriction indicator may have a low profile. The restriction indicator may be a visual restriction indicator with a wide viewing angle.

In one aspect, the present disclosure relates to an air cleaner assembly including a housing having an exterior surface around an interior volume. The housing includes a bore extending through a portion of the exterior surface of the housing along an insertion axis and surrounded by a bore wall protruding from the portion of the exterior surface along the insertion axis. The housing also includes a receptacle wall around the bore wall along the insertion axis and radially spaced from the bore wall to form a channel between the bore wall and the receptacle wall. The air cleaner assembly also includes a restriction indicator configured to measure a restriction in the interior volume when coupled to the housing and to display an indication of the restriction. The restriction indicator includes an indication element configured to display the indication of the restriction. The restriction indicator also includes a stem at least partially insertable into the bore along the insertion axis and configured to engage an inner surface of the bore wall when disposed therein. The restriction indicator further includes one or more tabs at least partially insertable in the channel between the bore wall and the receptacle wall and configured to facilitate removably coupling the restriction indicator to the housing.

It is to be understood that both the foregoing general description and the following detailed description present embodiments of the subject matter of the present disclosure and are intended to provide an overview or framework for understanding the nature and character of the subject matter of the present disclosure as it is claimed.

The present disclosure relates to an air cleaner assembly with a removable restriction indicator. Although reference is made herein to an air cleaner assembly for internal combustion engines, the air cleaner assembly may be used with any system in which monitoring fluid pressure may be desirable. Various other applications will become apparent to those of ordinary skill in the art having the benefit of the present disclosure.

The air cleaner assembly of the present disclosure provides a restriction indicator that may display visual information to users about when a filter needs service. The restriction indicator may be removably mounted to a housing of an air cleaner. The restriction indicator may be mounted by at least partially inserting a stem of the restriction indicator into a bore of the air cleaner housing. One or more tabs of the restriction indicator may engage one or more apertures of the housing to provide a snap-fit connection, which may facilitate quick installation or removal for service, particularly compared to other restriction indicators using a threaded connection. One or more rails may guide a tab toward a corresponding aperture during mounting to facilitate ease of installation. When mounted, the restriction indicator may have a low profile, which may mitigate damage to the restriction indicator by external forces.

The restriction indicator may show discrete states of the filter, such as no restriction, moderate restriction, and substantial restriction. The restriction indicator may employ a low number of calibration elements or only one calibration element to facilitate ease of assembly and calibrating for different applications. The restriction indicator may include a lock pin in a follower cam design, which may provide more accurate calibration and measurement points. The restriction indicator may include large indication regions <NUM>, <NUM>, <NUM> (<FIG>) to provide a wide viewing angle of the restriction indication.

<FIG> shows an air cleaner assembly <NUM> including a housing <NUM> and a restriction indicator <NUM>, for example, a visual restriction indicator, mounted to the housing along an axis <NUM>. The axis <NUM> may be described as an insertion axis or longitudinal axis. In particular, the restriction indicator <NUM> may be coupled to a receptacle <NUM> of the housing <NUM> along the axis <NUM>. The restriction indicator <NUM> and receptacle <NUM> may be designed to couple together using a low force directed along the axis <NUM>. For example, a maximum installation force to install the restriction indicator <NUM> may be less than or equal to about <NUM> lbs. , about <NUM> lbs. , about <NUM> lbs. , about <NUM> lbs. , about <NUM> lbs. , about <NUM> lbs. , about <NUM> lbs. , or about <NUM> lbs. The maximum installation force may be in a range of about <NUM> lbs. to about <NUM> lbs. , about <NUM> lbs. to about <NUM> lbs. , or about <NUM> lbs. to about <NUM> lbs. Preferably, the maximum installation force is in a range of about <NUM> lbs. to about <NUM> lbs. Preferably, the maximum installation force is equal to about <NUM> lbs.

The restriction indicator <NUM> may measure a restriction in an interior volume <NUM> defined by the housing <NUM> when the restriction indicator is coupled to the housing. An indication of the restriction may be displayed by the restriction indicator <NUM> that is visible to users.

The air cleaner assembly <NUM> may include a filter (not shown) for engine intake air in an internal combustion engine system. Part of the restriction indicator <NUM> may be exposed to the ambient environment and part of the restriction indicator may be exposed to the environment of the interior volume <NUM> to measure a pressure difference between the two environments. The portion of the restriction indicator <NUM> exposed to the environment of the interior volume <NUM> may be disposed downstream of the filter to detect vacuum pressure, or negative pressure, between the filter and an air intake manifold. When the filter is unloaded, or clean, there may be little or no vacuum pressure in the interior volume <NUM> of the air cleaner assembly <NUM> detected by the restriction indicator <NUM>. Typically, as the filter becomes more loaded, or dirty, more vacuum pressure builds in the interior volume <NUM> of the air cleaner assembly <NUM> that may be detected by the restriction indicator <NUM>.

The restriction indicator <NUM> may be calibrated for various applications. In some embodiments, for some internal combustion engine applications, the restriction indicator <NUM> may be calibrated to associate about <NUM>% loading of the filter with a vacuum pressure, which may vary depending on the particular application of the restriction indicator. In some embodiments, the vacuum pressure associated with about <NUM>% loading of the filter is equal to between about <NUM> and about <NUM> inches of H<NUM>O (water).

<FIG> shows part of the housing <NUM> and the restriction indicator <NUM> mounted to the housing in a perspective view after the restriction indicator <NUM> has been inserted along the axis <NUM> into the receptacle <NUM> of the housing <NUM>. As used herein, the axis <NUM> may be defined as parallel to a longitudinal direction and orthogonal to a lateral direction. The restriction indicator <NUM> may display an indication of the restriction when mounted to the receptacle <NUM> of the housing <NUM>. Although the axis <NUM> as shown extends through a center of the restriction indicator <NUM> and the receptacle <NUM>, the axis <NUM> need not necessarily extend through the center and/or may be tilted.

The housing <NUM> may be disposed around, or at least partially enclose, the interior volume <NUM> and may include an exterior surface <NUM>. At least a portion of the receptacle <NUM> may protrude from the exterior surface <NUM> along the axis <NUM>.

The receptacle <NUM> of the housing <NUM> may include a receptacle wall <NUM>. The receptacle wall <NUM> may protrude from the exterior surface <NUM> along the axis <NUM>. When mounted, at least a portion of the restriction indicator <NUM> may be disposed interior to the receptacle wall <NUM>.

The receptacle wall <NUM> may define one or more apertures <NUM> that extend through the receptacle wall. In <FIG>, only one aperture <NUM> is visible. Each aperture <NUM> may receive a portion of the restriction indicator <NUM> to facilitate securement of the restriction indicator <NUM> to the receptacle <NUM> of the housing <NUM>.

The restriction indicator <NUM> may include an indication element <NUM>, which may be externally visible to users through an at least partially, or entirely, clear cap <NUM> that covers the indication element. A reset knob <NUM> may be coupled to the indication element <NUM>. The cap <NUM> may be disposed between the indication element <NUM> and the reset knob <NUM>.

The cap <NUM> may extend around the axis <NUM> to cover the indication element <NUM>. The cap <NUM> may have a convex exterior surface <NUM> (<FIG>) that magnifies the indication of the restriction displayed on the indication element <NUM>. The indication of the restriction may be an icon, color, or other visual representation of a level of restriction of the air filter.

The indication element <NUM> may be capable of displaying a plurality of indications of restriction. In some embodiments, the indications of restriction may include one or more colors, such as red, yellow, and green. Red may indicate to users that filter replacement service may be needed (substantial vacuum pressure). For example, the red color may indicate almost or about <NUM>% loading of the filter. Yellow may indicate to users that a filter replacement service may be needed soon (moderate vacuum pressure). For example, the yellow color may indicate about <NUM>% loading of the filter. Green may indicate to users that there may be no substantial restriction in the filter and filter operation may be good (mild to no vacuum pressure). Each indication may be selectively displayed to correspond to the restriction of the air filter based on detected vacuum pressure.

The indication element <NUM> may rotate in a single direction about the axis <NUM> in response to increasing vacuum pressure. The indication displayed may depend on the amount that the indication element <NUM> has rotated. A mask <NUM> may be disposed between the indication element <NUM> and the cap <NUM>. A portion of the indication element <NUM> may be covered by a mask <NUM>, and a portion of the indication element may be visible through a window <NUM> (<FIG>) in the mask.

In some embodiments, at least a quarter of the indication element <NUM> may be visible through the window <NUM> (<FIG>) of the mask <NUM>. In other words, an arc segment of the indication element <NUM> that is greater than or equal to about <NUM> degrees may be visible through the window <NUM> of the mask <NUM>. In some embodiments, at least a third of the indication element <NUM> (greater than or equal to about <NUM> degrees) may be visible through the window <NUM> of the mask <NUM>. More visibility of the indication element <NUM> through the window <NUM> of the mask <NUM> may provide greater the visibility of the indication restriction for users.

The restriction indicator <NUM> may have a low profile when mounted. In particular, a portion of the restriction indicator <NUM> may extend along the axis <NUM> a limited distance beyond an upper edge <NUM> of the receptacle <NUM>. The upper edge <NUM> may be defined by the receptacle wall <NUM> of the receptacle <NUM> (see also <FIG>). The low profile of the restriction indicator <NUM> may be characterized by a maximum distance or height <NUM> (<FIG>) measured from the upper edge <NUM> of the receptacle wall <NUM>, or an outer shoulder <NUM> (<FIG>) of the restriction indicator, to the top of the restriction indicator, which may be the top of the reset knob <NUM>.

In some embodiments, the maximum height <NUM> (<FIG>) that the restriction indicator <NUM> extends along the axis <NUM> may be less than or equal to about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or less. Preferably, the maximum height <NUM> is less than or equal to about <NUM>. The maximum height <NUM> may be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. Preferably, the maximum height <NUM> is in a range of about <NUM> to about <NUM> (about <NUM> ± about <NUM>). In some embodiments, the maximum height <NUM> may be equal to about <NUM>.

<FIG> shows the receptacle <NUM> of the housing <NUM> separated from the restriction indicator <NUM> along the axis <NUM> with the restriction indicator being rotated about <NUM> degrees about the axis from a mounting orientation (see <FIG>). As can be seen, the receptacle <NUM> of the housing <NUM> may include a bore wall <NUM> having an inner surface <NUM> around a bore <NUM>. The bore wall <NUM> may protrude from the exterior surface <NUM> of the housing <NUM> along the axis <NUM>. The bore wall <NUM> may surround the bore <NUM> along the axis <NUM>. The bore <NUM> may extend along the axis <NUM> through the exterior surface <NUM> of the housing <NUM>.

The inner surface <NUM> may define the bore <NUM>. The shape of the inner surface <NUM> may include a cylindrical wall. A cross-sectional shape of the inner surface <NUM> may include a circle. The cross-section of the inner surface <NUM> may be defined by an intersection of a plane orthogonal to the axis <NUM> and the inner surface <NUM>. The circular cross-sectional shape of the inner surface <NUM> may be centered at the axis <NUM>.

The receptacle wall <NUM> may be disposed around the bore wall <NUM>. The receptacle wall <NUM> may protrude from the exterior surface <NUM> a distance along the axis <NUM> (for example, the distance between the exterior surface and the upper edge <NUM> of the receptacle wall), and such distance may be the same or greater than a distance that the bore wall <NUM> protrudes from the exterior surface along the axis <NUM>. In other words, the receptacle wall <NUM> may be taller than the bore wall <NUM>. In another manner of characterizing the relationship between the receptacle wall <NUM> and the bore wall <NUM>, the bore wall may be located between a plane occupied or defined by the upper edge <NUM> of the receptacle wall <NUM> and the exterior surface <NUM> of the housing <NUM>.

The receptacle wall <NUM> may be radially spaced from the bore wall <NUM> to form a channel <NUM> between the bore wall and the receptacle wall. The channel <NUM> may receive a portion of the restriction indicator <NUM> when mounted to the receptacle <NUM>. The portion of the restriction indicator <NUM> received in the channel <NUM> may engage the receptacle wall <NUM> proximate or adjacent to the apertures <NUM> to secure the restriction indicator <NUM> to the receptacle <NUM> of the housing <NUM>.

More than one aperture <NUM> may be formed in the receptacle wall <NUM>. In some embodiments, the number of apertures <NUM> extending through the receptacle wall <NUM> may be two, three, four, or more. Preferably, the receptacle wall <NUM> includes two apertures <NUM>. One aperture <NUM> may be disposed opposite another aperture <NUM> across the axis <NUM>. The channel <NUM> may be positioned proximate to one or more apertures <NUM>.

The restriction indicator <NUM> may include a stem <NUM> that extends along the axis <NUM> in a downward direction (toward the housing <NUM> as shown in <FIG>). The stem <NUM> may be at least partially insertable into the bore <NUM> along the axis <NUM>. The stem <NUM> may or may not engage the inner surface <NUM> of the bore wall <NUM> directly when the stem <NUM> is at least partially disposed in the bore <NUM> defined by the bore wall <NUM>.

The stem <NUM> may have an outer surface <NUM>. The shape of the outer surface <NUM> may include a cylindrical wall. A cross-sectional shape of the outer surface <NUM> may include a circle. The cross-section of the outer surface <NUM> may be defined by an intersection of a plane orthogonal to the axis <NUM> and the outer surface <NUM>. The circular cross-sectional shape of the outer surface <NUM> may be centered at the axis <NUM>.

The stem <NUM> may be defined by a maximum width <NUM> (<FIG>) orthogonal to the axis <NUM>. In particular, the outer surface <NUM> may define the maximum width <NUM>. The maximum width <NUM> may be defined as a diameter when the outer surface <NUM> has a circular cross-sectional shape. Preferably, the maximum width <NUM> of the stem <NUM> is less than or equal to a maximum width defined by the inner surface <NUM> of the bore wall <NUM> to facilitate insertion of the stem <NUM> into the bore <NUM>.

In some embodiments, the maximum width <NUM> of the stem <NUM> may be less than or equal to about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>. Preferably, the maximum width <NUM> is less than or equal to about <NUM>. The maximum width <NUM> may be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. Preferably, the maximum width <NUM> is in a range of about <NUM> to about <NUM>. Preferably, the maximum width <NUM> is equal to about <NUM>. In some embodiments, the tolerance of any of these values may be equal to about +/- <NUM> inches (<NUM>).

A sealing ring <NUM> may be disposed on the stem <NUM> of the restriction indicator <NUM>. In particular, the sealing ring <NUM> may be disposed around the stem <NUM>. The sealing ring <NUM> may facilitate engagement, or coupling, of the stem <NUM> to the inner surface <NUM> of the bore wall <NUM>. In particular, the sealing ring <NUM> may have a maximum width that is equal to or greater than the maximum width <NUM> (<FIG>) of the stem <NUM>. The sealing ring <NUM> may form a seal between the outer surface <NUM> of the stem and the inner surface <NUM> of the bore wall <NUM> when the restriction indicator <NUM> is at least partially inserted into the bore <NUM>. The sealing ring <NUM> may be formed of any compressible material suitable for forming an airtight seal when subjected to pressures of the particular application for which the restriction indicator <NUM> is designed. In some embodiments, the sealing ring <NUM> may be any suitable commercially available O-ring.

One or more tabs <NUM> may be aligned with (for example, extending parallel to) the axis <NUM> in the same downward direction as the stem <NUM>. The tabs <NUM> may also be described as "legs" of the restriction indicator <NUM>. The tabs <NUM> may be at least partially insertable in the channel <NUM> between the bore wall <NUM> and the receptacle wall <NUM>. The tabs <NUM> may be removably coupled to the receptacle wall <NUM> to secure the restriction indicator <NUM> to the housing <NUM>. In particular, the tabs <NUM> may be deflectable to couple or uncouple to the receptacle wall <NUM>. The tabs <NUM> may be formed of a resilient material capable of deflecting from a nominal shape in response to a lateral force and returning to the nominal shape in the absence of the lateral force.

A detent <NUM> may be disposed on any or all tabs <NUM>. Each detent <NUM> may be received in an aperture <NUM> of the receptacle wall <NUM> to facilitate securing the restriction indicator <NUM> to the housing <NUM>. In particular, a detent shoulder <NUM> may be disposed on any or all detents <NUM> that, when mounted, may engage an upper edge <NUM> (<FIG>) of the corresponding aperture <NUM> in the receptacle wall <NUM>. In some embodiments, the number of detents <NUM> received by the apertures <NUM> when the restriction indicator <NUM> is coupled to the housing <NUM> may be equal to one, two, three, four, or more detents. For example, in some embodiments, the restriction indicator <NUM> may include at most two detents (for example, one for each tab <NUM> when the restriction indicator has two tabs).

The restriction indicator <NUM> may be quickly and simply installed into the receptacle <NUM> of the housing <NUM>. The restriction indicator <NUM> may be coupled to the housing <NUM> by inserting the stem <NUM> at least partially into the bore <NUM> using a linear motion along the axis <NUM> to form a seal between the stem <NUM> and the bore wall <NUM> and to secure the one or more tabs <NUM> to the receptacle wall <NUM>. The sealing ring <NUM> may provide the seal, and the tabs <NUM> may form a snap-fit connection between the restriction indicator <NUM> and the receptacle wall <NUM> of the housing <NUM>. In this manner, the restriction indicator <NUM> may be conveniently nested into the receptacle <NUM> while achieving a low profile.

An inner surface <NUM> of the receptacle wall <NUM> may define an outer boundary of the channel <NUM>. The shape of the inner surface <NUM> may include a cylindrical wall. A cross-sectional shape of the inner surface <NUM> may include a circle. The cross-section of the inner surface <NUM> may be defined by an intersection of a plane orthogonal to the axis <NUM> and the inner surface <NUM>. The circular cross-sectional shape of the inner surface <NUM> may be centered at the axis <NUM>.

One or more guide rails <NUM> may be disposed in the channel <NUM> to facilitate installation of the restriction indicator <NUM>. Each guide rail <NUM> may be disposed proximate or adjacent to one of the apertures <NUM>. Each aperture <NUM> may be proximate or adjacent to one, two, three, four, or more guide rails <NUM>. Each guide rail <NUM> may extend into the channel <NUM> from the inner surface <NUM> of the receptacle wall <NUM>. The guide rails <NUM> may be integrally formed with the receptacle wall <NUM>. The guide rails <NUM> may have a maximum height measured from the exterior surface <NUM> of the housing <NUM> that is less than or equal to a maximum height of the receptacle wall <NUM>. In another manner of characterizing the relationship between the receptacle wall <NUM> and the guide rails <NUM>, the guide rails may be located between a plane occupied or defined by the upper edge <NUM> of the receptacle wall <NUM> and the exterior surface <NUM> of the housing <NUM>.

A tab <NUM> may be guided by one or more guide rails <NUM> as the restriction indicator <NUM> is at least partially inserted into the receptacle <NUM>. Each tab <NUM> may be guided by one, two, three, four, or more guide rails <NUM>. In some embodiments, any or all tabs <NUM> may each be guided by at least two guide rails <NUM>. Preferably, each tab <NUM> is guided by two guide rails <NUM> spaced from one another. When the restriction indicator <NUM> is coupled to the housing <NUM>, the tab <NUM> may fit between the space between the two guide rails <NUM>.

<FIG> shows the receptacle <NUM> of the housing <NUM> in an overhead view in the line with the axis <NUM>. As illustrated, the bore <NUM> extending through the exterior surface <NUM> of the housing <NUM> is surrounded by the inner surface <NUM> of the bore wall <NUM>. As shown, the inner surface <NUM> may have a circular cross-sectional shape centered at the axis <NUM>.

The channel <NUM> may be proximate or adjacent to the exterior surface <NUM> of the housing <NUM> between the bore wall <NUM> and the laterally spaced inner surface <NUM> of the receptacle wall <NUM>. The exterior surface <NUM> of the housing <NUM> may include a portion <NUM> that serves as a floor of the receptacle <NUM>, which may define a laterally extending boundary of the channel <NUM> between the bore wall <NUM> and the receptacle wall <NUM>.

Each guide rail <NUM> may extend into the channel <NUM> from the inner surface <NUM> proximate or adjacent to one of the apertures <NUM>. In some embodiments, two guide rails <NUM> may be proximate or adjacent to any or all apertures <NUM>. Preferably, the receptacle <NUM> of the housing <NUM> includes two apertures <NUM> and four guide rails <NUM>.

<FIG> shows the receptacle <NUM> of the housing <NUM> in a cross-sectional elevation view along line <NUM>-<NUM> in <FIG>. In the rotational orientation of the restriction indicator <NUM> about the axis <NUM>, as shown in <FIG>, the restriction indicator may be coupled to the receptacle <NUM> of the housing <NUM> using a linear motion along the axis. The bore <NUM> defined by the inner surface <NUM> of the bore wall <NUM> may be proximate or adjacent to the interior volume <NUM> defined by the housing <NUM>. The bore <NUM> extending through the portion <NUM> of the exterior surface <NUM> of the housing <NUM> may be in fluid communication with the interior volume <NUM> to allow vacuum pressure in the interior volume to be measured via the bore.

The receptacle wall <NUM> and the bore wall <NUM> may extend or protrude from the portion <NUM> of the exterior surface <NUM> in a direction that is aligned to the axis <NUM> (for example, parallel to). The inner surface <NUM> of the receptacle wall <NUM> may terminate at the upper edge <NUM>. The height of the bore <NUM> along the axis <NUM> may be defined by the bore wall <NUM> surrounding the bore.

A maximum height <NUM> of the restriction indicator <NUM> may be measured from the upper edge <NUM> of the receptacle wall <NUM> to the top of the reset knob <NUM> when the restriction indicator <NUM> is coupled to the housing <NUM>. The maximum height <NUM> of the restriction indicator <NUM> may also be measured between an outer shoulder <NUM> of a lower collar portion <NUM> of the restriction indicator <NUM> and the top of the reset knob <NUM>. These measurements of the maximum height <NUM> may be equivalent, or about the same, because the outer shoulder <NUM> may engage the upper edge <NUM> of the receptacle wall <NUM> when the restriction indicator <NUM> is coupled to the housing <NUM>.

A lower shell portion <NUM> of the restriction indicator <NUM> may extend between the stem <NUM> and the lower collar portion <NUM>. The stem <NUM>, lower collar portion <NUM>, and lower shell portion <NUM> may be part of an indicator housing <NUM>. In particular, the stem <NUM>, lower collar portion <NUM>, and lower shell portion <NUM> may be integrally formed as an indicator housing <NUM>. The stem <NUM> and the tabs <NUM> may each extend downwardly from the lower shell portion <NUM> of the indicator housing <NUM>.

The lower shell portion <NUM> may be defined by a maximum width <NUM> orthogonal to the axis <NUM>. The maximum width <NUM> may be defined as a diameter when the lower shell portion <NUM> has a circular cross-sectional shape. Preferably, the maximum width <NUM> of the lower shell portion <NUM> is less than or equal to a maximum width defined by the inner surface <NUM> of the receptacle wall <NUM> to facilitate insertion of the lower shell portion <NUM> of the restriction indicator <NUM> into the receptacle <NUM> of the housing <NUM>.

In some embodiments, the maximum width <NUM> of the lower shell portion <NUM> may be less than or equal to about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>. Preferably, the maximum width <NUM> is less than or equal to about <NUM>. The maximum width <NUM> may be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. Preferably, the maximum width <NUM> is in the range between about <NUM> and about <NUM>. Preferably, the maximum width <NUM> is equal to about <NUM>. In some embodiments, the tolerance of any of these values may be equal to about +/- <NUM> inches (<NUM>).

A maximum width <NUM> of the stem <NUM> orthogonal to the axis <NUM> may be defined by the outer surface <NUM> of the stem without the sealing ring <NUM>. In other embodiments, the maximum width <NUM> of the stem <NUM> may include the width of the sealing ring <NUM>. The maximum width <NUM> may allow a space between the stem <NUM> and the bore wall <NUM> when the stem is inserted into the bore <NUM> to accommodate the sealing ring <NUM> in a compressed state. In this manner, the stem <NUM> may be described as coupled or sealed indirectly to the bore wall <NUM>.

Each of the tabs <NUM> may be defined by a maximum width <NUM> orthogonal to the axis <NUM> in view of <FIG> (for example, a radial width as measured relative to axis <NUM>). Preferably, the maximum width <NUM> of the tab <NUM> is less than or equal to a maximum width defined by a space between corresponding guide rails <NUM> to facilitate fitting the tab between the guide rails.

In some embodiments, the maximum width <NUM> of any or all tabs <NUM> may be less than or equal to about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>. Preferably, the maximum width <NUM> is less than or equal to about <NUM>. The maximum width <NUM> may be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. Preferably, the maximum width <NUM> is in the range between about <NUM> to about <NUM>. Preferably, the maximum width <NUM> is equal to about <NUM>. In some embodiments, the tolerance of any of these values may be equal to about +/- <NUM> inches (<NUM>).

The detent <NUM> of any or all tabs <NUM> may have a maximum width <NUM> extending orthogonal to the axis <NUM> in view of <FIG> (for example, a radial width as measured relative to axis <NUM>), which may be the same or different than the maximum width <NUM> of the corresponding tab. Preferably, the maximum width <NUM> of the detent <NUM> is less than or equal to a maximum width defined by a corresponding aperture <NUM> (<FIG>) to facilitate fitting the detent into the aperture.

In some embodiments, the maximum width <NUM> of any or all detents <NUM> may be less than or equal to about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>. Preferably, the maximum width <NUM> is less than or equal to about <NUM>. The maximum width <NUM> may be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. Preferably, the maximum width <NUM> is in a range of about <NUM> to about <NUM>. Preferably, the maximum width <NUM> is equal to about <NUM>. In some embodiments, the tolerance of any of these values may be equal to about +/- <NUM> inches (<NUM>).

The cap <NUM> of the restriction indicator <NUM> may magnify the indication of restriction. In particular, the cap <NUM> may have a convex exterior surface <NUM>, or dome, which may magnify the indication of restriction for users viewing the restriction indicator <NUM> from a wide variety of angles - not only from a head-on view.

<FIG> shows the restriction indicator <NUM> in a cross-sectional elevation view along line <NUM>-<NUM> in <FIG> in an orientation capable of being coupled to the receptacle <NUM> of the housing <NUM>, as shown in <FIG> in a cross-sectional elevation view also along line <NUM>-<NUM>, with a linear movement along the axis <NUM>. As illustrated, the apertures <NUM> are disposed opposite one another across the axis <NUM>, and the tabs <NUM> are disposed opposite one another across the axis <NUM>.

The restriction indicator <NUM> may define a first distance <NUM> (<FIG>) to facilitate coupling to the receptacle wall <NUM> of the housing <NUM>. The first distance <NUM> may be aligned with (for example, extend parallel to) the axis <NUM> and be measured as the distance between the outer shoulder <NUM> of the lower collar portion <NUM> and the detent shoulder <NUM> of the detent <NUM>. The receptacle wall <NUM> may define a second distance <NUM> (<FIG>) to facilitate coupling to the restriction indicator <NUM>. The second distance <NUM> may be aligned with (for example, extending parallel to) the axis <NUM> and be measured as the distance between the upper edge <NUM> of the receptacle wall <NUM> and an upper edge <NUM> of the aperture <NUM>. A cooperative relationship between the first distance <NUM> and the second distance <NUM> may facilitate securing the restriction indicator <NUM> to the receptacle wall <NUM> of the housing <NUM>. In particular, the first distance <NUM> may be greater than or equal to the second distance <NUM>.

The first distance <NUM> may define a minimum distance between the outer shoulder <NUM> and the detent shoulder <NUM>. In some embodiments, the first distance <NUM> may be greater than or equal to about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>. Preferably, the first distance <NUM> is greater than or equal to about <NUM>. The first distance <NUM> may be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. Preferably, the first distance <NUM> is in a range of about <NUM> to about <NUM>. Preferably, the first distance <NUM> is equal to about <NUM>. In some embodiments, the tolerance of any of these values may be equal to about +/- <NUM> inches (<NUM>).

The restriction indicator <NUM> may define a third distance <NUM> (<FIG>) to facilitate coupling to the receptacle <NUM> of the housing <NUM>. The third distance <NUM> may be aligned with (for example, extending parallel to) the axis <NUM> and be measured as the distance between the outer shoulder <NUM> of the lower collar portion <NUM> and a bottom or lowest edge <NUM> of the tab <NUM>. The receptacle <NUM> may define a fourth distance <NUM> (<FIG>) to facilitate coupling to the restriction indicator <NUM>. The fourth distance <NUM> may be aligned with (for example, extending parallel to) the axis <NUM> and be measured as the distance between the portion <NUM> of the exterior surface <NUM> of the housing <NUM> (floor of the receptacle <NUM>) and the upper edge <NUM> of the receptacle wall <NUM>. A cooperative relationship between the third distance <NUM> and the fourth distance <NUM> may facilitate fitting and securing the restriction indicator <NUM> to the receptacle <NUM> of the housing <NUM>. In particular, the third distance <NUM> may be less than or equal to the fourth distance <NUM>.

The third distance <NUM> may define a maximum distance between the outer shoulder <NUM> and the lowest edge <NUM> of the tab <NUM>. In some embodiments, the third distance <NUM> may be less than or equal to about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>. The third distance <NUM> may be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. Preferably, the third distance <NUM> is in a range of about <NUM> to about <NUM>. Preferably, the third distance <NUM> is equal to about <NUM>.

A tortuous fluid communication path <NUM> (<FIG>) may be defined by the restriction indicator <NUM>. In general, the tortuous fluid communication path <NUM> may be disposed between the reset knob <NUM> and the cap <NUM>. In particular, the tortuous fluid communication path <NUM> may extend from a first end <NUM> in fluid communication with the ambient environment to a second end <NUM> in fluid communication with a first interior environment <NUM> of the restriction indicator <NUM>. The first end <NUM> may be disposed between an outer portion of the reset knob <NUM> and the cap <NUM>. The second end <NUM> may be disposed between an inner portion of the reset knob <NUM> and the cap <NUM>.

The tortuous fluid communication path <NUM> may provide a vent for the first interior environment <NUM> as vacuum pressure in the interior volume <NUM> is being measured. The tortuous fluid communication path <NUM> may include a plurality of bends between the first end <NUM> and the second end <NUM>, which may prevent contaminants, such as water, dirt, and oil, from entering the first interior environment <NUM>.

The first interior environment <NUM> may be defined between the diaphragm <NUM> and the cap <NUM>. The first interior environment <NUM> may be separated or sealed from a second interior environment <NUM> by the diaphragm <NUM>. The diaphragm <NUM> may be formed of any suitable flexible material capable of sealing, such as a silicone material. The second interior environment <NUM> may be in fluid communication with the interior volume <NUM> of the housing <NUM> via the bore <NUM> when the restriction indicator <NUM> is coupled to the receptacle <NUM> of the housing <NUM>. As vacuum pressure in the interior volume <NUM> changes, the diaphragm <NUM> may respond by raising or lowering, which may change the proportional volume between the first interior environment <NUM> and the second interior environment <NUM>.

<FIG> shows the restriction indicator <NUM> in an overhead view in line with the axis <NUM>. The cap <NUM> may extend around the reset knob <NUM> to cover the indication element <NUM>. The cap <NUM> may be entirely clear, transparent, or at least translucent enough to see the indication of restriction. The cap <NUM> may magnify the indication of restriction. The mask <NUM> may be disposed between the indication element <NUM> and the cap <NUM>. A window <NUM> may be defined by the mask <NUM> through which the indication element <NUM> may be viewed.

The indication element <NUM> may include a plurality of indication regions <NUM>, <NUM>, <NUM> each associated with different indications of restriction. The indication regions <NUM>, <NUM>, <NUM> may be about the same size or different sizes. The sizes may be characterized in terms of arc segment. In some embodiments, the indication element <NUM> includes three indication regions having an arc segment of about <NUM> degrees each.

As shown, only one of the indication regions <NUM> may be visible through the window <NUM> of the mask <NUM>. The other indication regions <NUM>, <NUM> may be visible through the window <NUM> of the mask <NUM> as the indication element <NUM> rotates in response to various vacuum pressures detected by the restriction indicator <NUM>. The restriction indicator <NUM> may be capable of rotating the indication element <NUM> greater than or equal to about <NUM> degrees, about <NUM> degrees, about <NUM> degrees, or about <NUM> degrees. Greater rotation capability may facilitate larger sizes of the indication regions <NUM>, <NUM>, <NUM>.

Each indication region <NUM>, <NUM>, <NUM> may be fully displayed through the window <NUM> of the mask <NUM> (one at a time). Preferably, each indication region <NUM>, <NUM>, <NUM> has a size greater than or equal to the size of the window <NUM>.

<FIG> shows the restriction indicator <NUM> in a cutaway perspective view. <FIG> show various components of the restriction indicator <NUM> in exploded perspective views selected to show the upper and lower surfaces of the components. In particular, the various components are shown separated along the axis <NUM>. In general, many of the components of the restriction indicator <NUM> have rotationally symmetric dimensions about the axis <NUM>, which may facilitate movement of a generally circular-shaped indication element <NUM>.

The restriction indicator <NUM> may include one or more of the reset knob <NUM>, cap <NUM>, indication element <NUM>, torsional spring <NUM>, diaphragm <NUM>, lock pin <NUM>, calibration element <NUM>, indicator housing <NUM>, and sealing ring <NUM>. The indicator housing <NUM> may include a channel <NUM> to retain the sealing ring <NUM>.

The restriction indicator <NUM> may utilize a follower cam design to translate the linear motion of the diaphragm <NUM> into rotational motion of the indication element <NUM> to provide an indication of a restriction or remaining filter life. As the calibration element <NUM>, diaphragm <NUM>, and lock pin <NUM> move in linear correlation to the vacuum level, an indexing or advancing geometry may be used to provide an indication of increased vacuum pressure. In particular, the indication element <NUM> includes different levels of cam steps <NUM>, <NUM>, <NUM> that interact with the lock pin <NUM>. Although the follower cam sign may utilize one or more calibration elements <NUM>, the follower cam design may utilize only one calibration element <NUM> to achieve vacuum pressure detection.

An outer portion of the diaphragm <NUM> may form a seal between the cap <NUM> and the indicator housing <NUM> to prevent fluid communication between environments in the restriction indicator <NUM>. Changes in vacuum pressure may move the diaphragm <NUM> generally upward or downward along the axis <NUM>. In some embodiments, the cap <NUM> may be ultrasonically welded to the indicator housing <NUM>. In other embodiments, the cap <NUM> may be integrally formed with the indicator housing <NUM>.

An inner portion of the diaphragm <NUM> may seal to the lock pin <NUM>. As the diaphragm <NUM> moves, the lock pin <NUM> will move in the same direction. A lower portion of the lock pin <NUM> may be guided along the axis <NUM> by rotational lock element <NUM>. The rotational lock element <NUM> may be a protrusion extending upward from the indicator housing <NUM>. The protrusion may have a triangular cross-sectional shape. An upper portion of the lock pin <NUM> may be guided along the axis <NUM> by a passage <NUM> formed in the indication element <NUM>. Guided by the rotational lock element <NUM> and the passage <NUM>, the lock pin <NUM> may be described as a floating lock pin relative to other components of the restriction indicator <NUM>.

The torsional spring <NUM> may be coupled between the indication element <NUM> and the cap <NUM>. The torsional spring <NUM> may be described as a "clock" spring that spirals from an inner portion to an outer portion. In particular, the inner portion may be coupled to the indication element <NUM>, and the outer portion may be coupled to the cap <NUM> or indicator housing <NUM>. The torsional spring <NUM> may apply a load to the indication element <NUM> that encourages the indication element to rotate in a single direction (for example, clockwise or counter-clockwise) from an indication that the filter is not restricted (for example, a green indication region) toward an indication that the filter is moderately restricted (for example, a yellow indication region) and toward an indication that the filter is substantially restricted (for example, a red indication region).

The rotation of the indication element <NUM> about the axis <NUM> may be impeded by an interaction with the lock pin <NUM>. The lock pin <NUM> may include a follower protrusion <NUM>. The follower protrusion <NUM> may engage a cam disposed on a lower portion of the indication element <NUM> having various cam steps <NUM>, <NUM>, <NUM>. Each cam step <NUM>, <NUM>, <NUM> may have a different height and be associated with a different indication region of the indication element. The height transition between each step <NUM>, <NUM>, <NUM> may define discrete positions for the follower protrusion <NUM> to lock the indication element <NUM> relative to the lock pin <NUM>.

The follower protrusion <NUM> in cooperation with the cam steps <NUM>, <NUM>, <NUM> may allow the restriction indicator <NUM> to maintain and display the restriction of the air filter, even when the engine is turned off and there is no vacuum pressure detected. This may facilitate checking the condition of the air filter, even when the engine is off.

For example, the first cam step <NUM> may be associated with the lock pin <NUM> being in a highest position in the restriction indicator <NUM> and associated with displaying a green indication region of the indication element <NUM> to users. The follower protrusion <NUM> may rest at the height transition between the first cam step <NUM> and the second cam step <NUM> to display the green indication region.

As vacuum pressure increases due to restriction of the filter, the lock pin <NUM> may move linearly downward, which may cause the follower protrusion <NUM> to separate vertically from the first cam step <NUM> and toward the level of the second cam step <NUM>. The indication element <NUM> may not move linearly in response to increased vacuum pressure to facilitate the separation. Once the follower protrusion <NUM> reaches the level of the second cam step <NUM>, the height transition between the first and second cam steps <NUM>, <NUM> no longer impedes the rotation of the indication element <NUM>. The torsional spring <NUM> may rotate the indication element <NUM> so that the follower protrusion <NUM> travels across the second cam step <NUM> and rests at the height transition between the second and third cam steps <NUM>, <NUM>. In this position, the restriction indicator <NUM> may display a yellow indication region of the indication element <NUM> to users.

Then, as vacuum pressure further increases due to restriction of the filter, the lock pin <NUM> may move linearly downward even further, which may cause the follower protrusion <NUM> to separate vertically from the second cam step <NUM> toward the level of the third cam step <NUM>. Once the follower protrusion <NUM> reaches the level of the third cam step <NUM>, the height transition between the second and third cam steps <NUM>, <NUM> no longer impedes the rotation of the indication element <NUM>. The torsional spring <NUM> may rotate the indication element <NUM> so that the follower protrusion <NUM> travels across the third cam step <NUM> and rests at a stop on the opposite side of the third cam step. In this position, the restriction indicator <NUM> may display a red indication region of the indication element <NUM> to users. Although only three cam steps <NUM>, <NUM>, <NUM> are described herein, additional cam steps may be provided to correspond to more graduations of filter loading. The indication element <NUM> may be configured accordingly based on the additional cam steps to visually indicate the graduations. For example, restriction indicator may provide three or more levels of restriction indication regions and associated cam steps, such as <NUM>, <NUM>, <NUM>, or <NUM> levels.

An upper portion of the indication element <NUM> may be coupled to the reset knob <NUM>. In particular, the reset knob <NUM> may be coupled to the indication element <NUM> using a snap-fit connection. The upper portion of the indication element <NUM> may include a rotational lock element <NUM> so that rotating the reset knob <NUM> also rotates the indication element <NUM> and vice versa. The rotational lock element <NUM> may include a lateral protrusion.

The calibration element <NUM> may be disposed between the lock pin <NUM> and the indicator housing <NUM>. The calibration element <NUM> may be a spring. The calibration element <NUM> may provide a force that encourages the lock pin <NUM> away from the indicator housing <NUM>, for example, in an upward direction along the axis <NUM>. The calibration element <NUM> may have a predetermined spring force based on a particular application. For example, the predetermined spring force may be selected based on the expected nominal pressure in the interior volume of the air cleaner assembly and an expected pressure change corresponding to restriction of the air filter. In other words, the linear movement of the lock pin <NUM> in response to vacuum pressure may be based on the spring force of the calibration element <NUM>.

Once a filter has been replaced, the reset knob <NUM> may be rotated manually by the user to cause the indication element <NUM> to rotate in a direction that reloads the torsional spring <NUM>. The follower protrusion <NUM> may travel across the cam steps <NUM>, <NUM>, <NUM> in reverse order (from cam step <NUM> to cam step <NUM> to cam step <NUM>). The restriction indicator <NUM> may be fully reset when the follower protrusion <NUM> is positioned at the height transition between the first and second cam steps <NUM>, <NUM> so that the green indication region is displayed.

<FIG> show an air cleaner assembly <NUM> including a housing <NUM> and a restriction indicator <NUM> for mounting to the housing. <FIG> shows the restriction indicator <NUM> positioned near the housing <NUM> at the beginning of installation. <FIG> shows the restriction indicator <NUM> installed in the housing <NUM>. <FIG> shows a view from the inside of a cutaway of housing <NUM> when the restriction indicator <NUM> is inserted before the restriction indicator <NUM> is rotated into a finally installed position. <FIG> shows a view from the inside of another cutaway of housing <NUM> when the restriction indicator <NUM> is installed in the housing <NUM>. Air cleaner assembly <NUM> may have an even lower profile than air cleaner assembly <NUM> when installed, which may be beneficial in some applications.

The air cleaner assembly <NUM> is like the air cleaner assembly <NUM> and may include one or more of the same aspects. Reference is made to the discussion above regarding <FIG> for elements depicted in but not specifically discussed with regard to <FIG>. The air cleaner assembly <NUM> may functionally differ from the air cleaner assembly <NUM> in that, instead of a single insertion motion along a longitudinal axis to install the restriction indicator into the housing, the restriction indicator <NUM> may be installed with an insertion motion along a longitudinal axis followed by a rotational motion, or twist. When installed, the restriction indicator <NUM> may operate like the restriction indicator <NUM>. Although illustrated as separate embodiments, various aspects of the air cleaner assembly <NUM> may be used with the air cleaner assembly <NUM>, and vice versa.

In the illustrated embodiment, the air cleaner assembly <NUM> differs from the air cleaner assembly <NUM> in that the restriction indicator <NUM> includes a raised portion <NUM> and one or more lateral tabs <NUM> and in that the housing <NUM> includes one or more latch portions <NUM>, one or more ramp portions <NUM>, and one or more pockets <NUM> (for example, instead of apertures <NUM>). The one or more lateral tabs <NUM>, the one or more latch portions <NUM>, and the one or more pockets <NUM> may facilitate removably, or releasably, coupling the restriction indicator <NUM> to the housing <NUM>. Further, according to the invention, a portion <NUM> (<FIG>) of the exterior surface <NUM> of the housing <NUM> is recessed from a surrounding portion <NUM> of the exterior surface <NUM>, and the receptacle wall <NUM> extends between the portion <NUM> and the surrounding portion <NUM>. The recessed portion <NUM> and receptacle wall <NUM> may form a well type of receptacle <NUM> that can receive the restriction indicator <NUM> for installation.

In some embodiments, the recessed portion <NUM> may include a downwardly extending protrusion <NUM>. The protrusion <NUM> may include an aperture <NUM> in fluid communication with the interior of the housing <NUM> and the interior of the receptacle <NUM>.

The cap <NUM> of restriction indicator <NUM> may have a raised portion <NUM>. The raised portion <NUM> may extend at least partially around the restriction indicator <NUM>. The raised portion <NUM> may extend in an arc segment that is smaller than, larger than, or that coincides with the arc segment of the indication of restriction, or window in the mask.

The raised portion <NUM> may facilitate viewing the indication of restriction inside the restriction indicator <NUM> from a shallow angle. The cap <NUM> may include the raised portion <NUM> and a low-profile portion <NUM>. The low-profile portion <NUM> may be positioned adjacent to the raised portion <NUM>. In general, the raised portion <NUM> may have a steeper slope than the low-profile portion <NUM>. The raised portion <NUM> may include a laterally facing section <NUM> (e.g., lateral section), one or more side facing sections <NUM> (e.g., side sections), and a top facing section <NUM> (e.g., top section). The laterally facing section <NUM> may have a steeper slope than the low-profile portion <NUM>. The one or more side facing sections <NUM> may also have a steeper slope than the low-profile portion <NUM>. In some embodiments, the laterally facing section <NUM> and the top facing section <NUM> may form an angle greater than or equal to about <NUM>, <NUM>, or <NUM> degrees (e.g., measured using vectors orthogonal to the respective surfaces or average orthogonal vectors for non-planar surfaces).

In one step of installation, restriction indicator <NUM> may be inserted into the receptacle <NUM> of the housing <NUM> such that the one or more lateral tabs <NUM> contact the exterior surface <NUM> of the surrounding portion <NUM> of the housing <NUM>. In some embodiments, the one or more lateral tabs <NUM> may extend outwardly from the cap <NUM>. In the illustrated embodiment, the upper edge <NUM> of the receptacle <NUM> is flush with the exterior surface <NUM> of the surrounding portion <NUM>. The receptacle wall <NUM> may include a shoulder <NUM> that engages the outer shoulder <NUM> of the restriction indicator <NUM> when inserted into the receptacle <NUM>.

In another step of installation, for example, after the one or more lateral tabs <NUM> contact the exterior surface <NUM> of the housing <NUM> (see <FIG>), the restriction indicator <NUM> may be rotated such that the one or more lateral tabs <NUM> engage with, or are received into, the one or more latch portions <NUM> to releasably secure the restriction indicator <NUM> to the housing <NUM> (see <FIG> and <FIG>). The one or more lateral tabs <NUM> may extend laterally outward from the restriction indicator as opposed to, for example, extending downward like tabs <NUM>. Each lateral tab <NUM> may include an axially extending protrusion <NUM> (e.g., outwardly axial protrusion). When a lateral tab <NUM> is inserted into a latch portion <NUM>, the latch portion <NUM> may include a shoulder <NUM> that releasably engages the axially extending protrusion <NUM>. In particular, the latch portion <NUM> may deflect as the axially extending protrusion <NUM> engages the shoulder <NUM> of the latch portion <NUM> and the latch portion <NUM> may relax after the axially extending protrusion <NUM> passes the shoulder <NUM>. The shoulder <NUM> may engage the axially extending protrusion <NUM> to prevent rotational movement in a rotational direction. When a lateral tab <NUM> is received into a latch portion <NUM>, movement of the restriction indicator <NUM> may be prevented in the axial directions and in one or two rotational directions.

When the restriction indicator <NUM> is inserted into the receptacle <NUM>, the one or more tabs <NUM> may engage the receptacle wall <NUM> and be deflected laterally inwardly. The one or more pockets <NUM> may be positioned on the receptacle wall <NUM> such that when the one or more lateral tabs <NUM> are rotated into the one or more latch portions <NUM>, each tab <NUM> may be rotated into a respective pocket <NUM>. When the tab <NUM> is releasably engaged with, or received into, the respective pocket <NUM>, the tab <NUM> may relax and prevent movement of the restriction indicator <NUM> in one or two rotational directions. The restriction indicator <NUM> may be fully installed when the one or more lateral tabs <NUM> are received in, or engaged with, the one or more latch portions <NUM> and the one or more tabs <NUM> are received in, or engaged with, the one or more pockets <NUM>. The restriction indicator <NUM> may not be easily removed from the receptacle <NUM> without a threshold amount of rotational force.

In the illustrated embodiment, each pocket <NUM> is aligned with a respective latch portion <NUM>, and each lateral tab <NUM> is aligned with a respective tab <NUM>. In other embodiments, one or more pockets <NUM> may not be aligned with a respective latch portion <NUM> and/or one or more lateral tabs <NUM> may not be aligned with a respective tab <NUM>.

Also, in the illustrated embodiment, the restriction indicator <NUM> may include two tabs <NUM> and two lateral tabs <NUM>, and the housing <NUM> may include two latch portions <NUM> and two pockets <NUM>. Any suitable number of one or more tabs <NUM>, lateral tabs <NUM>, latch portions <NUM>, and pockets <NUM> may be used to secure the restriction indicator <NUM> to the housing <NUM>.

Further, as illustrated, each pocket <NUM> is integrally formed as a single piece with the receptacle wall <NUM>. The exterior side of each pocket <NUM> protrudes from the exterior of the receptacle wall <NUM>. In other embodiments, one or more pockets <NUM> may be separately formed from the receptacle wall <NUM> and/or the exterior side of one or more pockets <NUM> may not protrude from the exterior of the receptacle wall <NUM>. In general, each pocket <NUM> may be located to suitably engage a tab <NUM>, and each latch portion <NUM> may be located to suitably engage a lateral tab <NUM>, and vice versa.

In some embodiments, each pocket <NUM> may have two edges that each extend axially to define a radial width of the pocket. When installed, each tab <NUM> may be seated between both edges of the pocket <NUM>. One or both edges may be gradual (e.g., less than about <NUM> degrees, such as about <NUM> degrees) or sharp (e.g., about <NUM> degrees). In some embodiments, one edge may be gradually sloped, and the other edge may be sharply sloped. A gradual edge may allow the tab <NUM> to slide out of the pocket <NUM> for removal. A sharp edge may prevent the tab <NUM> from over-rotating past the pocket <NUM> for installation.

The housing <NUM> may include one or more ramp portions <NUM> on the exterior surface <NUM> of the surrounding portion <NUM>. Each ramp portion <NUM> may be positioned to engage the one or more lateral tabs <NUM> when the restriction indicator <NUM> is inserted in the receptacle <NUM>. Each ramp portion <NUM> may be positioned proximate, near, or adjacent to a respective latch portion <NUM>. Each ramp portion <NUM> may reinforce the respective latch portion <NUM> and may also facilitate appropriate tactile feedback. For example, when the restriction indicator <NUM> is rotated in the wrong direction for installation, the rotation of the restriction indicator <NUM> will not be stopped because the one or more lateral tabs <NUM> will ride over one or more ramp portions <NUM> and over the respective latch portions <NUM>. Whereas when rotating the restriction indicator <NUM> in the correct direction for installation, the one or more lateral tabs <NUM> will engage the one or more latch portions <NUM> and rotation will be stopped. In some embodiments, one or more ramp portions <NUM> may be integrally formed as a single piece, or separately formed, with the one or more latch portions <NUM>. The one or more ramp portions <NUM> may be integrally formed as a single piece, or separately formed, with the housing <NUM>.

<FIG> show a restriction indicator <NUM> for mounting to a housing, such as housing <NUM> or <NUM>. The restriction indicator <NUM> is like the restriction indicators <NUM> and <NUM> and may include one or more of the same aspects. Reference is made to the discussion above regarding <FIG> for elements depicted in but not specifically discussed with regard to <FIG>. For example, as illustrated, the restriction indicator <NUM> is like restriction indicator <NUM> in that restriction indicator <NUM> includes a cap <NUM> having a raised portion <NUM>. and one or more lateral tabs <NUM> configured to engage a housing, such as housing <NUM>. However, restriction indicator <NUM> differs from restriction indicator <NUM> in that restriction indicator <NUM> includes one or more user engageable tabs <NUM>.

The one or more user engageable tabs <NUM> may be manually grasped by a user to twist, or rotate, the restriction indicator <NUM> during installation or removal. The one or more user engageable tabs <NUM> may be located in any suitable location on the cap <NUM>. For example, each user engageable tab <NUM> may be integrally formed with a respective lateral tab <NUM> into a single piece or separately formed from the lateral tabs <NUM>.

In general, the one or more user engageable tabs <NUM> may extend axially in an upward direction and may also extend laterally from an outer perimeter, or edge, of the cap <NUM> inward toward a center of the cap <NUM>. For example, each user engageable tab <NUM> may extend away from the housing when the restriction indicator <NUM> is installed in the housing. However, any suitable orientation and size of user engageable tab <NUM> may be used to facilitate torqueing the restriction indicator <NUM> during installation or removal, for example, by hand to facilitate the ease of installation and service.

Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "about. " Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

The terms "coupled" or "connected" refer to elements being attached to each other either directly (in direct contact with each other) or indirectly (having one or more elements between and attaching the two elements).

Terms related to orientation, such as "up," "down," "upper," "lower," "top," "bottom," "end," "longitudinal," "lateral," and other similar terms are used to describe relative positions of components and are not meant to limit the orientation of the embodiments contemplated. For example, an embodiment described as having a "top" and "bottom" also encompasses embodiments thereof rotated in various directions unless the content clearly dictates otherwise.

Other embodiments may also be preferred, under the same or other circumstances.

As used herein, "have," "having," "include," "including," "comprise," "comprising" or the like are used in their open-ended sense, and generally mean "including, but not limited to". It will be understood that "consisting essentially of," "consisting of," and the like are subsumed in "comprising," and the like.

Claim 1:
An air cleaner assembly (<NUM>) comprising:
a housing (<NUM>) comprising an exterior surface (<NUM>) around an interior volume (<NUM>), the housing (<NUM>) comprising:
a bore (<NUM>) extending through a portion of the exterior surface (<NUM>) of the housing (<NUM>) along an insertion axis (<NUM>) and surrounded by a bore wall (<NUM>) protruding from the portion of the exterior surface (<NUM>) along the insertion axis (<NUM>), wherein the portion of the exterior surface (<NUM>) is recessed from a surrounding portion of the exterior surface (<NUM>); and
a receptacle wall (<NUM>) around the bore wall (<NUM>) along the insertion axis (<NUM>) and radially spaced from the bore wall (<NUM>) to form a channel between the bore wall (<NUM>) and the receptacle wall (<NUM>), wherein the receptacle wall (<NUM>) extends between the portion of the exterior surface (<NUM>) and the surrounding portion of the exterior surface (<NUM>); and
a restriction indicator (<NUM>; <NUM>) configured to measure a restriction in the interior volume (<NUM>) when coupled to the housing (<NUM>) and to display an indication of the restriction, the restriction indicator (<NUM>; <NUM>) comprising:
an indication element (<NUM>) configured to display the indication of the restriction;
a stem (<NUM>) at least partially insertable into the bore (<NUM>) along the insertion axis (<NUM>) and configured to engage an inner surface (<NUM>) of the bore wall (<NUM>) when disposed therein; and
one or more tabs (<NUM>) at least partially insertable in the channel between the bore wall (<NUM>) and the receptacle wall (<NUM>) and configured to facilitate removably coupling the restriction indicator (<NUM>; <NUM>) to the housing (<NUM>).