Patent Description:
Conventional fuel filters are often made using plastic components that are spin-welded to join particular plastic components, such as the base plate and canister, for example. However, spin welding plastic components has proven problematic for a variety of reasons. The spin welding process typically requires complex equipment set up and operation, challenging weld joint geometries, and can be made more difficult by variations in the raw materials. All of these issues may lead to delays in production and/or expensive and time-consuming product failures during development and manufacturing. Therefore, it would be advantageous to have a method of assembly for such fuel filters that does not include spin welding. Such a method would provide significant benefit by eliminating failures and the delays and associated costs that come with the spin welding process.

The following documents may provide technical background to the present disclosure: <CIT>; <CIT>; <CIT>; <CIT>.

Embodiments of the invention detailed below represent an improvement to the state of the art with respect to hydraulic filtration devices. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

Embodiments of the present invention address some of the concerns set forth above by disclosing a fuel filter replacement, such as might be used in a diesel engine for example, where the fuel filter does not require spin welding to join to pressure critical plastic components, as in conventional fuel filters.

As defined in appended claim <NUM>, a filter cartridge includes a canister configured to hold a filter element. The canister has a canister body with an open end and an end closure. The end closure has a central annular element locating feature, and an annular frame portion circumscribing the central annular element locating feature. The canister body and end closure have cooperating geometry for retaining the end closure to the open end of the canister. The cooperating geometry includes an axial retention mechanism for maintaining an attachment between the canister and the end closure. The axial retention mechanism is configured to maintain the attachment solely via mechanical interference.

In some embodiments, the axial retention mechanism includes an internal annular rib circumscribing an inner surface of the canister, proximate the open end, and an external annular rib circumscribing an outer surface of the flexible portion of the end closure. The external annular rib of the flexible portion of the end closure is configured and arranged to engage the internal annular rib of the canister when the end closure is attached to the open end of the canister. The internal annular rib may extend continuously around the inner surface of the canister. In particular embodiments, the internal annular rib has an average height of five hundredths of an inch with respect to the inner surface of the canister.

In a further embodiment, the external annular rib extends continuously around the outer surface of the flexible portion of the end closure. In more particular embodiments, the external annular rib has an average height of ten hundredths of an inch with respect to the outer surface of the flexible portion of the end closure. In other embodiments, the mechanical interference between the external annular rib and the internal annular rib is at least three hundredths of an inch. As specified in this application, the dimension associated with mechanical interference refers to the distance that one component extends past the closest point of a second component. Thus, the aforementioned embodiment indicates that the external annular rib extends at least three hundredths of an inch beyond the closed part of the internal annular rib and vice versa.

In another embodiment of the invention, an axial end of the flexible portion of the end closure is chamfered to facilitate insertion of the end closure into the canister body. In some embodiments, the end closure includes a groove that extends around a circumference of an outer perimeter surface of the annular frame portion, where the groove is configured to seat an O-ring.

In an alternate embodiment, the axial retention mechanism includes an internal annular rib circumscribing an inner surface of the canister, proximate the open end, and a plurality of flexible tabs spaced around a perimeter edge section of the frame portion. The flexible tabs on the perimeter edge section of the frame portion project in a direction axially inwardly into the canister and are configured and arranged to engage the internal annular rib of the canister when the end closure is attached to the open end of the canister. The flexible tabs may be evenly spaced around the perimeter edge section of the frame portion. Additionally, the flexible tabs may each have a radially outward facing snap tab portion. The filter cartridge may further include a series of axial ribs on the inner surface of the canister extending toward the open end of the canister at least as far as the internal annular rib, where the flexible tabs are arranged to fit between the axial ribs when the end closure is attached to the canister in order to prevent rotation of the end closure relative to the canister body. In some particular embodiments, the internal annular rib has an average height of ten hundredths of an inch with respect to the inner surface of the canister.

In certain particular embodiments, the axial retention mechanism includes a series of axial ribs on an inner surface of the canister, each of which has a shoulder at a distal end of each rib proximate the open end of the canister, and a plurality of flexible tabs spaced around a perimeter edge section of the frame portion. The flexible tabs on the perimeter edge section of the frame portion may project in a direction axially inwardly into the canister, and may be configured and arranged to engage the shoulder of the axial ribs on the canister when the end closure is attached to the open end of the canister. In a more particular embodiment, the plurality of flexible tabs is evenly spaced around the perimeter edge section of the frame portion, and the series of axial ribs is evenly spaced around the inner surface of the canister such that each flexible tab is engaged with a respective axial rib when the end closure is attached to the open end of the canister.

In a further embodiment, each flexible tab includes a slotted portion in which the respective axial rib is seated, wherein the seating of the flexible tab in the slotted portion acts to prevent rotation of the end closure relative to the canister. Additionally, the flexible tabs may each have a radially outward facing snap tab portion, such that the mechanical interference between the outward facing snap tab portion and the shoulder provides axial retention. In more particular embodiments, the mechanical interference between the radially outward facing snap tab portion and the shoulder is at least three hundredths of an inch. The end closure may include a first groove that extends around a circumference of an outer perimeter surface of the annular frame portion, the first groove being configured to seat an O-ring. Furthermore, the canister may include a second groove around a circumference of the inner surface located proximate the first groove when the end closure is attached to the open end of the canister, where the second groove is configured to seat the O-ring.

In yet another embodiment of the invention, the cooperating geometry further includes an anti-rotation mechanism for preventing rotation of the base plate relative to the canister, the anti-rotation mechanism configured to prevent rotation of the base plate relative to the canister solely via mechanical interference. In a particular embodiment, the anti-rotation mechanism has a plurality of axial locating slots and axial locating tabs spaced apart around a perimeter edge section of the frame portion and an outer edge of the open end of the canister. The axial locating tabs and axial locating slots may be configured and arranged to interengage to rotationally align the end closure and the canister when the end closure is attached to the open end of the canister. In some embodiments, the end closure further includes a plurality of radial support ribs projecting between the element locating feature and the rigid attachment portion of the frame portion.

In an alternate embodiment, the anti-rotation mechanism has a plurality of radially-inward projecting tabs spaced apart around the circumference of the interior surface of the canister, and a plurality of radially-inward projecting slots spaced around a perimeter surface of an annular frame portion of the end closure. The engagement between each of the plurality radially-inward projecting tabs and a respective radially-inward projecting slot prevents rotation of the end closure relative to the canister.

On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

<FIG> is a cross-sectional view of a filter cartridge <NUM>, constructed in accordance with an embodiment of the invention. The filter cartridge <NUM> includes a canister <NUM> and a base plate which is referred to herein as an end closure <NUM>. The base plate or end closure is typically attached to the canister to hold the filter element in place. In the embodiment shown, the canister <NUM> is configured to hold a filter element <NUM> when the end closure <NUM> is attached to the canister <NUM>. <FIG> shows a perspective view of the end closure <NUM> for the filter cartridge <NUM>, constructed in accordance with an embodiment of the invention. <FIG> shows a perspective view of a cross-section for an end portion of the canister <NUM> for the filter cartridge <NUM> showing an inner surface <NUM> of the canister <NUM>, along with an enlarged cross-section of the end closure <NUM> of <FIG> attached to the canister <NUM>. <FIG> is a cross-sectional view of the end closure <NUM>, according to an embodiment of the invention.

In certain embodiments of the invention, the canister <NUM> has a canister body <NUM> with an open end in which the end closure <NUM> is inserted to attach to the canister <NUM>. The end closure <NUM> has a central annular element locating feature <NUM> that defines a central opening <NUM>, and an annular frame portion <NUM> circumscribing the central annular element locating feature <NUM>. In a more particular embodiment, the annular frame portion <NUM> circumscribing the element locating feature <NUM> includes an annular rigid attachment portion <NUM> and an annular flexible portion <NUM> projecting from the rigid attachment portion <NUM>. In embodiments of the invention, the end closure <NUM> is made from a resilient material such as plastic. As such, because it is not stiffened by support ribs <NUM>, the flexible portion <NUM> is able to move slightly during assembly of the end closure <NUM> to the canister <NUM>.

In the embodiment shown, the end closure <NUM> includes a plurality of radial support ribs <NUM> projecting between the element locating feature <NUM> and the annular frame portion <NUM> to support and connect the central annular element locating feature <NUM> and annular frame portion <NUM>. In alternate embodiments, the element locating feature <NUM> and annular frame portion <NUM> may be connected by spokes, a solid flat plate, an angled flat plate, or a wedge-shaped plate.

In certain embodiments, the canister body <NUM> and end closure <NUM> have cooperating geometry for retaining the end closure <NUM> to the open end of the canister <NUM>. The cooperating geometry may include an axial retention mechanism for maintaining an attachment between the canister <NUM> and the end closure <NUM>. In the embodiments shown, the axial retention mechanism is configured to maintain the aforementioned attachment solely via mechanical interference.

In some embodiments, the axial retention mechanism includes an internal annular rib <NUM> circumscribing an inner surface <NUM> of the canister <NUM>, proximate the open end, and an external annular rib <NUM> circumscribing an outer surface <NUM> of the flexible portion <NUM> of the end closure. The external annular rib <NUM> of the flexible portion <NUM> of the end closure <NUM> is configured and arranged to engage the internal annular rib <NUM> of the canister <NUM> when the end closure <NUM> is attached to the open end of the canister <NUM>. The internal annular rib <NUM> may extend continuously around the inner surface <NUM> of the canister <NUM>. In particular embodiments, the internal annular rib <NUM> has an average height of five hundredths of an inch with respect to the inner surface <NUM> of the canister <NUM>.

In a further embodiment, the external annular rib <NUM> extends continuously around the outer surface <NUM> of the flexible portion <NUM> of the end closure <NUM>. In more particular embodiments, the external annular rib <NUM> has an average height of ten hundredths of an inch with respect to the outer surface <NUM> of the flexible portion <NUM> of the end closure <NUM>. In other embodiments, the mechanical interference between the external annular rib <NUM> and the internal annular rib <NUM> is at least three hundredths of an inch. As specified in this application, the dimension associated with mechanical interference refers to the distance that one component extends past the closest point of a second component. Thus, the aforementioned embodiment indicates that the external annular rib <NUM> extends at least three hundredths of an inch beyond the closed part of the internal annular rib <NUM> and vice versa.

In another embodiment of the invention, an axial end <NUM> of the flexible portion <NUM> of the end closure <NUM> is chamfered to facilitate insertion of the end closure <NUM> into the canister body <NUM>. In some embodiments, the end closure <NUM> includes a groove <NUM> that extends around a circumference of the outer perimeter surface of the annular rigid attachment portion <NUM>, where the groove <NUM> is configured to seat an O-ring <NUM>.

<FIG> is a perspective view of a different embodiment of an end closure <NUM> for the filter cartridge <NUM>, constructed in accordance with an embodiment of the invention different from that of <FIG>. <FIG> is a cross-sectional view of the canister <NUM> for filter cartridge <NUM> along with a close-up cross-sectional view of the end closure <NUM> of <FIG> attached to the canister <NUM>, according to an embodiment of the invention.

Like the end closure <NUM> of <FIG>, the end closure <NUM> of <FIG> has a central annular element locating feature <NUM> that defines a central opening, and an annular frame portion <NUM> circumscribing the central annular element locating feature <NUM>. In embodiments of the invention, the end closure <NUM> is made from a resilient material such as plastic. In the embodiment shown, the end closure <NUM> includes a plurality of radial support ribs <NUM> projecting between the element locating feature <NUM> and the annular frame portion <NUM> to support and connect the central annular element locating feature <NUM> and annular frame portion <NUM>. In alternate embodiments, the element locating feature <NUM> and annular frame portion <NUM> may be connected by spokes, a solid flat plate, an angled flat plate, or a wedge-shaped plate. Additionally, the end closure <NUM> may include a groove <NUM> that extends around a circumference of an outer perimeter surface of the annular frame portion <NUM>, with the groove <NUM> being configured to seat the O-ring <NUM> (shown in <FIG>).

In this embodiment, the axial retention mechanism includes the internal annular rib <NUM> circumscribing the inner surface <NUM> of the canister <NUM> proximate the open end, and a plurality of flexible tabs <NUM> spaced around a perimeter edge section of the frame portion <NUM>. The flexible tabs <NUM> on the perimeter edge section of the frame portion <NUM> project in a direction axially inwardly into the canister <NUM> and are configured and arranged to engage the internal annular rib <NUM> of the canister <NUM> when the end closure <NUM> is attached to the open end of the canister <NUM>. The flexible tabs <NUM> may be evenly spaced around the perimeter edge section of the frame portion <NUM>. Additionally, the flexible tabs <NUM> may each have a radially outward facing snap tab portion <NUM>. Additionally, the outward facing snap tab portion <NUM> may be chamfered to facilitate insertion of the end closure <NUM> into the canister body <NUM>.

The filter canister <NUM> may further include a series of axial ribs <NUM> on the inner surface <NUM> of the canister <NUM> extending toward the open end of the canister <NUM> at least as far as the internal annular rib <NUM>, where the flexible tabs <NUM> are arranged to fit between the axial ribs <NUM> when the end closure <NUM> is attached to the canister <NUM> in order to prevent rotation of the end closure <NUM> relative to the canister body <NUM>. During insertion of the end closure <NUM> into the canister <NUM>, the flexible tabs <NUM> flex radially inward as the radially outward facing snap tab portion <NUM> engages the internal annular rib <NUM>. As the radially outward facing snap tab portion <NUM> moves past the internal annular rib <NUM>, the flexible tab <NUM> flexes back to its normal position. The mechanical interference between the snap tab portion <NUM> and the internal annular rib <NUM> provide axial retention between the end closure <NUM> and the canister <NUM>. In some particular embodiments, the internal annular rib <NUM> has an average height of ten hundredths of an inch with respect to the inner surface <NUM> of the canister <NUM>.

<FIG> is a perspective view of yet another end closure <NUM> for the filter cartridge <NUM>, constructed in accordance with an embodiment of the invention different from that of <FIG> and <FIG>. <FIG> is an enlarged cross-sectional view of the end closure <NUM> of <FIG> shown attached to the canister <NUM>, according to an embodiment of the invention. <FIG> is an enlarged perspective view of an interior portion of the canister <NUM>, according to an embodiment of the invention.

Like the end closures <NUM>, <NUM> described above, the end closure <NUM> of <FIG> has a central annular element locating feature <NUM> that defines a central opening, and an annular frame portion <NUM> circumscribing the central annular element locating feature <NUM>. In embodiments of the invention, the end closure <NUM> is made from a resilient material such as plastic. In the embodiment shown, the end closure <NUM> includes a plurality of radial support ribs <NUM> projecting between the element locating feature <NUM> and the annular frame portion <NUM> to support and connect the central annular element locating feature <NUM> and annular frame portion <NUM>. In alternate embodiments, the element locating feature <NUM> and annular frame portion <NUM> may be connected by spokes, a solid flat plate, an angled flat plate, or a wedge-shaped plate.

In this embodiment, the axial retention mechanism includes a series of axial ribs <NUM> on an inner surface <NUM> of the canister <NUM>, each of which has a shoulder <NUM> at a distal end of each rib <NUM> proximate the open end of the canister <NUM>, and a plurality of flexible tabs <NUM> spaced around a perimeter edge section of the frame portion <NUM>. The flexible tabs <NUM> on the perimeter edge section of the frame portion <NUM> may project in a direction radially inwardly into the canister <NUM>, and may be configured and arranged to engage the shoulder <NUM> of the axial ribs <NUM> on the canister <NUM> when the end closure <NUM> is attached to the open end of the canister <NUM>.

In a more particular embodiment, the plurality of flexible tabs <NUM> is evenly spaced around the perimeter edge section of the frame portion <NUM>, and the series of axial ribs <NUM> is evenly spaced around the inner surface <NUM> of the canister <NUM> such that each flexible tab <NUM> is engaged with a respective axial rib <NUM> when the end closure <NUM> is attached to the open end of the canister <NUM>. During insertion of the end closure <NUM> into the canister <NUM>, the flexible tabs <NUM> flex radially inward as the radially outward facing snap tab portion <NUM> engages the shoulder <NUM>. As the radially outward facing snap tab portion <NUM> moves past the shoulder <NUM>, the flexible tab <NUM> flexes back to its normal position.

In a further embodiment, each flexible tab <NUM> includes a slotted portion <NUM> in which the respective axial rib <NUM> is seated. The slotted portion <NUM> has edge members <NUM> positioned on each side of the axial rib <NUM> when the rib <NUM> is seated in the slotted portion <NUM>. The seating of the flexible tab <NUM> in the slotted portion acts to prevent rotation of the end closure <NUM> relative to the canister <NUM>. Additionally, the flexible tabs <NUM> may each have a radially outward facing snap tab portion <NUM>, such that the mechanical interference between the outward facing snap tab portion <NUM> and the shoulder <NUM> provides the axial retention. In more particular embodiments, the mechanical interference between the radially outward facing snap tab portion <NUM> and the shoulder <NUM> is at least three hundredths of an inch.

As used in this application, the dimension associated with mechanical interference refers to the distance that one component extends past the closest point of a second component. Thus, the preceding exemplary embodiment is one in which the radially outward facing snap tab portion <NUM> extends at least three hundredths of an inch beyond the closed part of the shoulder <NUM> and vice versa. In a particular embodiment, the outward facing snap tab portion <NUM> is chamfered to facilitate insertion of the end closure <NUM> into the canister body <NUM>.

The end closure <NUM> may include a first groove <NUM> that extends around a circumference of an outer perimeter surface of the annular frame portion <NUM>, the first groove <NUM> being configured to seat the O-ring <NUM>. <FIG> shows a close-up cross-sectional view of the first groove <NUM> of the end closure <NUM> attached to the canister <NUM>. The O-ring <NUM> is omitted from this view to make it easier to see the features of the end closure <NUM> and canister <NUM>. In this embodiment, the canister <NUM> may include a second groove <NUM> that extends around a circumference of the inner surface <NUM> located proximate the first groove <NUM> when the end closure <NUM> is attached to the open end of the canister <NUM>, where the second groove <NUM> is also configured to seat the O-ring <NUM> (shown in <FIG>). Compression of the O-ring <NUM> in the first groove <NUM> and second groove <NUM>, when the end closure <NUM> is attached to the canister <NUM>, aids in the axial retention and in preventing rotation of the end closure <NUM> with respect to the canister <NUM>.

<FIG> is a perspective side view of an end closure <NUM> with radial splines <NUM>, constructed in accordance with an embodiment of the invention, while <FIG> shows an enlarged perspective view of the end closure <NUM> and of a radial spline <NUM>. <FIG> is an enlarged view of a portion of the canister <NUM> showing a mating notch <NUM> to accommodate the radial spline <NUM> of <FIG>, in accordance with an embodiment of the invention. <FIG> is a perspective view of a portion of the end closure <NUM> attached to a filter cartridge canister <NUM>, in accordance with an embodiment of the invention. For the sake of clarity, <FIG> only shows the portion of the end closure <NUM> with the radial spline <NUM> and the portion of the canister <NUM> with the mating notches <NUM> that engage the radial splines <NUM>.

Like the end closures <NUM>, <NUM>, <NUM> described above, the end closure <NUM> of <FIG> has a central annular element locating feature <NUM> that defines a central opening, and an annular frame portion <NUM> circumscribing the central annular element locating feature <NUM>. In embodiments of the invention, the end closure <NUM> is made from a resilient material such as plastic. In the embodiment shown, the end closure <NUM> includes a plurality of radial support ribs <NUM> projecting between the element locating feature <NUM> and the annular frame portion <NUM> to support and connect the central annular element locating feature <NUM> and annular frame portion <NUM>. In alternate embodiments, the element locating feature <NUM> and annular frame portion <NUM> may be connected by spokes, a solid flat plate, an angled flat plate, or a wedge-shaped plate.

In this embodiment, the cooperating geometry of the end closure <NUM> and canister <NUM> as described above, constitutes an anti-rotation mechanism for preventing rotation of the end closure <NUM> relative to the canister <NUM>. Further, this anti-rotation mechanism is configured to prevent rotation of the end closure <NUM> relative to the canister <NUM> solely via mechanical interference. As shown in <FIG>, the end closure <NUM> has a plurality of axially-extending (and radially-extending) radial splines <NUM>, which function as locating tabs, spaced apart around a perimeter edge section of the frame portion <NUM>. The radial splines <NUM> may be evenly spaced around the entire circumference of the annular frame portion <NUM> though embodiments with uneven spacing of radial splines <NUM> is envisioned. Additionally, the end closure <NUM> may include a groove <NUM> that extends around a circumference of an outer perimeter surface of the annular frame portion <NUM>, the groove <NUM> being configured to seat the O-ring <NUM> (shown in <FIG>).

The canister <NUM> includes a plurality of mating notches <NUM> which are shown as axially-extending locating slots spaced apart around an outer edge of the open end of the canister <NUM>. The radial splines <NUM> and mating notches <NUM> may be configured and arranged to interengage to rotationally align the end closure <NUM> and the canister <NUM> when the end closure <NUM> is attached to the open end of the canister <NUM>.

Another anti-rotation mechanism is shown in <FIG>. In this embodiment, the canister <NUM> includes a plurality of radially-inward projecting tabs <NUM> spaced apart around the circumference of the interior surface <NUM> of the canister <NUM>. The radially-inward projecting tabs <NUM> are designed the engage a plurality of radially-inward projecting slots <NUM> spaced around a perimeter surface of an annular frame portion <NUM> of the end closure <NUM>. When the end closure <NUM> is assembled to the canister <NUM>, each of the radially-inward projecting tabs <NUM> seats with a radially-inward projecting slot <NUM>. This engagement between radially-inward projecting tabs <NUM> and radially-inward projecting slot <NUM> prevents rotation of the end closure <NUM> relative to the canister <NUM>.

Like the end closures <NUM>, <NUM>, <NUM>, <NUM> described above, the end closure <NUM> of <FIG> has a central annular element locating feature <NUM> that defines a central opening, and an annular frame portion <NUM> circumscribing the central annular element locating feature <NUM>. In embodiments of the invention, the end closure <NUM> is made from a resilient material such as plastic. In the embodiment shown, the end closure <NUM> includes a plurality of radial support ribs <NUM> projecting between the element locating feature <NUM> and the annular frame portion <NUM> to support and connect the central annular element locating feature <NUM> and annular frame portion <NUM>.

The foregoing description discloses exemplary embodiments of a fuel filter with external housing components that are assembled via mechanical interference connection. For an all-plastic spin-on filter, the base plate or end closure could be threaded into the filter canister or these two components could be spin welded to form the necessary attachment. Threading is very time-consuming as the parts must be aligned, as it takes a fair amount of time to run the threads together. As explained above, spin welding has certain shortcomings as well. Assembling the components by relying on mechanical interference to maintain the attachment is a faster alternative to threading without all the complications that come with spin welding.

Claim 1:
A filter cartridge (<NUM>) comprising:
a canister (<NUM>) configured to hold a filter element (<NUM>), the canister (<NUM>) having a canister body (<NUM>) with an open end and an end closure (<NUM>), the end closure (<NUM>) having:
a central annular element locating feature (<NUM>); and
an annular frame portion (<NUM>) circumscribing the central annular element locating feature (<NUM>);
wherein the canister body (<NUM>) and end closure (<NUM>) have cooperating geometry for retaining the end closure (<NUM>) to the open end of the canister, the cooperating geometry including:
an axial retention mechanism for maintaining an attachment between the canister (<NUM>) and the end closure (<NUM>), the axial retention mechanism configured to maintain the attachment solely via mechanical interference.