Abstract:
A filter assembly employs inward and outward radially displaced portions of a peripheral shoulder on the cartridge as components of a cartridge compatibility matrix. Alternative base assemblies include mounting structures complementary to the configuration of the peripheral shoulder to exclude incompatible cartridges. The peripheral shoulder is preferably a roll seam connecting first and second sections of the filter housing. The invention further contemplates a pattern of radial protrusions from a portion of the cartridge housing received in a base receptacle as part of a cartridge compatibility matrix. The base receptacle is configured to receive only those cartridges having a compatible pattern of radial protrusions. A cartridge compatibility matrix including both inward and outward deformations of a cartridge peripheral shoulder and radial protrusions of the received portion of the cartridge housing can ensure both cartridge compatibility and a particular mounted position of the cartridge relative to the base.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to fuel filters employed in connection with internal combustion engines. More particularly, the present invention relates to replaceable fuel filter cartridges for removing foreign particles and/or separating water from the fuel supply system of an internal combustion engine. 
     2. Description of the Related Art 
     Fuel filter systems to which the invention relates commonly employ a disposable filter cartridge that is replaced at pre-established intervals of filter usage. The replaceable cartridge is conventionally secured to a base that defines inlet and outlet connections between the cartridge and the fuel supply system. Numerous retention systems have been employed for securing the filter cartridge to the base and allowing removal of the cartridge for replacement purposes. 
     In practice, filter cartridge requirements may vary depending upon: the type and make of the internal combustion engine; the specific application for which the engine is employed; the climate in which the engine is operated; and/or regional characteristics as to the quality of the fuel supply. Filter cartridges suitable for replacement in a particular filtration system, commonly vary as to capacity, fluid compatibility and filter media qualities. 
     One of the recurring problems in assuring filtration system performance is encountered in connection with replacement of the filter cartridge. It is imperative that the replacement cartridge be compatible with the filtering requirements for the fuel system. It is common for filter cartridges to have a generally similar exterior configuration regardless of performance. As a result, a replacement filter cartridge may dimensionally conform to the base of a given fuel filter assembly, and not comply with the applicable specifications for the fuel system and thereby jeopardize the integrity of the fuel filtering system. Replacement with an incompatible filter cartridge can have very serious consequences for the operation of the internal combustion engine and may also be unnecessarily more expensive than less costly cartridges which are fully suitable. In practice, replacement cartridges may be so similar in overall configuration that the owner of the vehicle and/or the maintenance technician servicing the internal combustion engine may unknowingly jeopardize the integrity of the filtering system by replacement with a wholly unsuitable cartridge even though the unsuitable cartridge at least cursorily appears to be suitable. There are also, of course, instances where inferior or improper replacement filter cartridges are intentionally installed without the knowledge of the owner of the operator of the vehicle. 
     For many applications, it is also desirable that a cartridge be mounted to the base at a specific angular orientation so that warnings, directions and markings affixed to the cartridge may be properly positioned to ensure visibility and maximize the chances of successful information dissemination. For other applications, it is desirable that the cartridge be locked in position relative to the base such that the cartridge may not rotate with relation to the base. 
     U.S. Pat. No. 5,035,797, which is assigned to the assignee of the present invention, discloses a fuel filter assembly in which a base mounts to the vehicle and a disposable filter cartridge is suspended from the base. The cartridge is retained to the base by a threaded collar that engages against a protruding roll seam structure at the periphery of the cartridge housing. The cartridge is replaced by loosening the threaded collar and dismounting the filter cartridge. A key system is disclosed in which keys axially project from the base through corresponding slots in the end cap of the filter cartridge housing. The dimensions and location of the axially projecting keys ensure compatibility by interfering with mounting and sealing of incompatible cartridges lacking the correct slot configuration. The keys interlock with the slots to mount the cartridge at a fixed angular relationship to the base. 
     U.S. Pat. No. 5,837,137, which is assigned to the assignee of the present invention, discloses a similarly configured fuel filtration assembly (e.g., the cartridge is retained to the base by a threaded collar) incorporating an alternative location and key system. Protrusions from a receiving surface of the base are received in corresponding dimples in the opposing end surface of the cartridge to lock the cartridge at a fixed angular position relative to the base. The protrusions interfere with the mounting and sealing of a non-compatible cartridge having an incompatible pattern of dimples. 
     A further variation on ensuring compatibility in fuel filtration assemblies similar to those described above is disclosed in U.S. Pat. No. 5,766,463, which is assigned to the assignee of the present invention. The disclosed fuel filter cartridge is formed from a pair of shell sections joined along a roll seam to form the retaining shoulder. The generally cylindrical upper portion of the filter cartridge is received within the base. A plurality of arcuate protrusions radially project from the cylindrical upper portion of the cartridge to be received in compatible tracks in the base. The protrusions are disclosed as part of a key code system including the key/slot system described in the &#39;797 patent. A keying system that relies on protrusions from the received portion of the cartridge housing may permit defeat of the keying system by allowing a cartridge without the protrusions to be received in the keyed base without interference. 
     An alternative filter cartridge mounting system is disclosed in U.S. Pat. No. 6,187,188, also assigned to the assignee of the present invention. The roll seam at the junction of the cartridge housing sections is radially outwardly displaced to form a plurality of retention tabs. The base includes a fixed retaining structure comprising a retaining lip defining a plurality of axial slots in communication with retaining channel portions above the retaining lip. The axial slots are located and dimensioned to be complementary to the retaining tabs of the filter cartridge. The filter cartridge is retained to the base by axially aligning the tabs with the slots and upwardly displacing the cartridge into the receptacle of the base. The cartridge is then rotated so that the tabs are engaged within the retaining channel portions. The &#39;188 patent discloses that compatibility of the cartridge with the base may be ensured by providing the received portion of the cartridge with arcuate slots to accommodate keys axially projecting from the base as disclosed in the &#39;797 patent. Alternatively, the received portion of the cartridge may be provided with radial protrusions such as those disclosed in the &#39;463 patent. Tracks in the base for receiving the protrusions must be L-shaped (have an axial portion and a radial portion) to accommodate rotation of the cartridge relative to the base. 
     Ensuring filter cartridge compatibility is an issue of continuing concern in the art. While the approaches to ensuring filter cartridge compatibility described in the &#39;797, &#39;137, &#39;463, and &#39;188 patents represent significant advances over the prior art, further improvements in effectiveness and efficiency are possible. For example, keys projecting from the base that require openings in the filter cartridge compromise the sealed integrity of the filtration system. Keying arrangements that restrict the cartridge to a fixed angular position relative to the base are incompatible with filter assemblies that require rotation of the cartridge relative to the base. The L-shaped tracks disclosed in the &#39;188 patent may be difficult to produce, thereby increasing the cost of filter assemblies. 
     There is an ongoing need in the art for a filter assembly that prevents installation of incompatible filter cartridges. Ideally, a filter cartridge compatible with such a key system may be employed with a filter assembly in which the cartridge is retained to the base by a collar and filter assemblies in which the cartridge is rotated to engage radially projecting tabs in a retainer fixedly extending from the base. 
     SUMMARY OF THE INVENTION 
     A first aspect of the present invention pertains to inward and outward displacement of a roll seam at the junction of housing sections of a filter cartridge to provide components of a cartridge compatibility matrix. Portions of the roll seam are radially outwardly offset to form retention tabs. Further portions of the roll seam are radially inwardly displaced relative to the remainder of the roll seam. In one embodiment, the cartridge housing is substantially symmetric about a central axis, and the retention tabs are equiangularly spaced about the axis. The tabs are also substantially equivalent in angular extent and radial displacement, i.e., the tabs have the same general configuration. Consequently, the roll seam includes three substantially equal length portions extending between the retention tabs. One or more of these roll seam portions may include a segment that is inwardly displaced with respect to the central axis. The receptacle of a compatible base is provided with structures permitting reception and sealing of a cartridge with a complementary pattern of retention tabs and inward displaced segments. A non-compatible cartridge, for example a cartridge with a similar arrangement of retention tabs but lacking the requisite inwardly displaced segments of the roll seam, is prevented from mating with the base. 
     In a base with a fixed retainer where the retention tabs are axially received through slots and the cartridge secured to the base by rotation relative to the base, compatibility is ensured by inward protrusions on the retainer lip. The inward protrusions of the retaining lip correspond to the inwardly displaced segments of the roll seam and allow axial reception of the roll seam through the retaining lip. The roll seam of an incompatible filter cartridge will lack the correct arrangement of inwardly displaced portions of the roll seam will be prevented from axial reception into the base. In one cartridge compatibility matrix, the roll seam includes three equiangularly spaced retention tabs and three equiangularly spaced inwardly displaced segments of the roll seam. Alternatively, the inwardly displaced portions may be non-symmetrical to ensure a particular installed orientation of the cartridge relative to the base. 
     In addition, the filter cartridge may also comprise at least one outward protrusion from the side wall of that portion of the cartridge received in the base. Rather than an L shaped track in the base receptacle, a ring at the entrance to the receptacle defines axial openings compatible with the protrusions on the cartridge. Together, the configuration of the roll seam and the received portion of the cartridge may be incorporated into multiple levels of keying for cartridge identification, cartridge positioning and quality control purposes. 
     Another aspect of the present invention relates to a filter assembly where a cartridge of the present invention is retained to a base by a collar. An annular lip of the base axially protrudes into a space defined between the roll seam and the received portion of the filter cartridge. The configuration of this space is complementary with the configuration of the roll seam, e.g., the retention tabs increase the radial dimension of the space and the inwardly displaced segments of the roll seam decrease the radial dimension of the space. The axially protruding lip of the base is provided with outward protrusions complementary with the retention tabs and locations where lip material is removed to accommodate inwardly displaced segments of the roll seam. 
     An object of the present invention is to provide a new and improved filter cartridge compatibility matrix. 
     Another object of the present invention is to provide a new and improved filter cartridge structure that ensures compatibility in filter assemblies having fixed and movable cartridge-retention systems. 
     A further object of the present invention is to provide a new and improved filter assembly in which compatibility protection cannot be defeated by omission of the compatibility matrix structure from the cartridge. 
     Other objects and advantages of the invention will become apparent from the drawings and the specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings in which: 
         FIG. 1  is a vertical sectional view, partly broken away, of a fuel filter cartridge incorporating a compatibility matrix exemplary of several aspects of the present invention; 
         FIG. 2  is a top plan view of the filter cartridge of  FIG. 1 ; 
         FIG. 3  is an enlarged view of an inwardly displaced segment of the roll seam of the filter cartridge of  FIG. 2 ; 
         FIG. 4  is an enlarged sectional view through the roll seam at the left side of the filter cartridge of  FIG. 1 ; 
         FIG. 5  is an enlarged portion of the filter cartridge shown in  FIG. 2  illustrating a retention tab formed from an outward deformation of the roll seam; 
         FIG. 6  is a front view of a portion of a first filter base component configured to receive the filter cartridge of  FIG. 1 ; 
         FIG. 7  is a side view of the filter base component of  FIG. 6 ; 
         FIG. 8  is a top view of the filter base component of  FIG. 6 ; 
         FIG. 9  is a sectional view of the filter base component of  FIG. 6 , taken along line  9 — 9  thereof; 
         FIG. 10  is a bottom view, partly in phantom, of the filter base component of  FIG. 6 ; 
         FIG. 11  is a sectional view of the filter base component of  FIG. 6 , taken along line  11 — 11  thereof; 
         FIG. 12  is a side view of a second filter base component configured to receive the filter cartridge of  FIG. 1 ; 
         FIG. 13  is a bottom view of the filter base component of  FIG. 12 ; 
         FIG. 14  is bottom view, partly in phantom, of a retaining collar for retaining the filter cartridge of  FIG. 1  to the base component of  FIGS. 12 and 13 ; and 
         FIG. 15  is a sectional view of the collar of  FIG. 14 , taken along line  15 — 15  thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of a filter cartridge illustrating several aspects of the present invention will now be described with particular reference to  FIGS. 1-5 . A first embodiment of a filter base component compatible with the cartridge of  FIGS. 1-5  is shown in  FIGS. 6-11 . A second embodiment of a filter base component compatible with the cartridge of  FIGS. 1-5  is shown in  FIGS. 12-15 . 
       FIG. 1  is a sectional view through an exemplary filter cartridge  10  comprising a first housing section  12  joined to a second housing section  14  along a peripheral roll seam  16 .  FIG. 4  illustrates an enlarged sectional view through the roll seam  16  on the left hand side of FIG.  1 . The sheet metal of the respective housing sections which forms the roll seam is shown as dotted lines to the left and right of the filter cartridge  10  adjacent the roll seam in FIG.  1 . The sheet metal extending from the housing first section  12  extends radially beyond the sheet metal of extending from the housing second section  14 . When rolled together to form the roll seam shown in  FIG. 4 , the extended radial length of the sheet metal of the housing first section  12  is rolled under and overlaps the sheet metal of the housing second section  14 . The rolled, overlapping sheet metal is then crimped to form the roll seam in a manner known in the art. A U-shaped bend in the housing first section  12  inwardly of the roll seam defines a space  20  between the roll seam and the housing first section  12 . This space  20  allows access to the interior of the roll seam  16  during seam formation and for the purposes of deformation as will be discussed below. 
     The filter cartridge  10  has an overall general configuration and functionality that is well understood by those of skill in the art. A filter element  18  is supported within the filter cartridge. A grommet  30  surrounds an axial opening  32  in the housing first section  12  that receives coaxial conduits (not shown) for delivery of unfiltered fluid and retrieval of filtered fluid from the filter cartridge  10 . The housing second section  14  may be provided with a drain cock  60  for removal of water that may accumulate in a sump  15  defined by the lower portion of the housing second section  14 . 
       FIG. 2  is a top view of the filter cartridge of FIG.  1 . The roll seam  16  circumscribes the filter cartridge  10  radially separated from the housing first section  12  to define an annular space  20 . The roll seam  16  includes three portions that are radially outwardly displaced relative to the central axis A of the cartridge to form retention tabs  24 . The retention tabs  24  are illustrated as being equiangularly arranged on the circumference of the roll seam and of equal angular extent and radial displacement. Three roll seam portions  23  extend between the retention tabs  24 . In the illustrated embodiment, each of these portions  23  of the roll seam include a radially inwardly displaced segment  22 . The inwardly displaced segments  22  provide one variable for use in conjunction with a cartridge compatibility matrix. The inwardly displaced segments  22  of the roll seam  16  on the exemplary filter cartridge  10  are diametrically opposed to each retention tab  24 . 
     The inward and outward displacement of the roll seam relative to its generally circular shape result in a serpentine configuration. This complex shape is advantageously located at the radial outer periphery of the filter cartridge. As will be discussed in greater detail below, a compatibility matrix including a serpentine, or convoluted outer periphery of the filter cartridge presents unique opportunities for blocking reception of cartridges omitting portions of the compatibility matrix. Further, inward and outward displacement of the roll seam  16  relative to the central axis A of the cartridge defines an annular space  20  having a variable radial dimension when measured perpendicular to the cartridge axis A, as best seen in FIG.  2 . The shape of the annular space  20  may be used as part of a cartridge compatibility matrix when the cartridge  10  is mounted to a base including the component shown in  FIGS. 12 and 13  by the collar shown in  FIGS. 14 and 15 . In accordance with a further aspect of the present invention, the outer profile of the roll seam  16  is used as a constituent of a cartridge compatibility matrix when the cartridge  10  is mounted to a base including the component shown in  FIGS. 6-11 . 
       FIG. 3  illustrates an enlarged view of an inwardly displaced segment  22  of the roll seam  16 . In the illustrated embodiment, the inward displacement of the roll seam is in the form of an arc having a radius of curvature of approximately 2.5″ and a center of curvature located outside the roll seam  16 . The inward deformation displaces the roll seam  16  inwardly from its normal radius of curvature  17  (illustrated by the dashed line in  FIG. 3 ) by a distance in the range of 0.02″ to 0.05″ at the center of the deformation. The inwardly displaced segment has a length of approximately 0.5″ measured along the circumference of the roll seam. Alternatively, the inwardly displaced segment may be configured as a substantially linear portion  22   a  of said shoulder  16 . 
       FIG. 5  is an enlarged portion of  FIG. 2  illustrating the outward displacement of the roll seam  16  to form a retention tab  24 . The roll seam is radially outwardly displaced by a distance of approximately 0.08″ relative to adjacent portions of the roll seam or a distance approximately equivalent to the radial thickness of the roll seam  16 . Each retention tab  24  of the illustrated embodiment maintains its maximum outward displacement (of approximately one roll seam thickness) for approximately 0.5″. It will be appreciated that the roll seam  16  includes transitional portions  24   a  adjacent either end of the retention tabs. The roll seam  16  between the retention tabs  24  (including their transitional portions  24   a ) and the inwardly displaced segments  22  maintain a substantially constant radius of curvature centered on the cartridge axis A. 
       FIGS. 6-11  illustrate one component of a first embodiment of a filter base configured to mount the filter illustrated in  FIGS. 1-5 . The illustrated component  40  of a filter base is a molded member with integrally extending bracket portions  42 . The bracket portions  42  are configured to receive a reinforcing metal sleeve (not shown) through which an attachment bolt (not shown) retains the filter base to a support structure (not shown). Below the bracket portions, the illustrated base component  40  comprises a generally cylindrical wall  46  that defines a receptacle  47  for axially receiving the filter cartridge housing first section  12 . An axial central conduit  48  of the base component  40  is received and sealingly engaged by a grommet  30  of an installed filter cartridge  10 . The cylindrical wall  46  flares to include a fixed integral retainer  44 . The retainer  44  comprises three axial slots  51  complementary to the radially projecting retention tabs  24  on the cartridge  10 . The axial slots  51  communicate with retaining channel portions  43  partially defined by a retaining lip upper surface comprising a ramp  52  and a seat  54 . 
     The first housing section  12  of the filter cartridge  10  is axially inserted into the receptacle  47  until the retaining tabs  24  are aligned with the retaining channel portions  43 . The cartridge  10  is then rotated clockwise relative to the base. During rotation, the retaining tabs ride up the ramps  52  and over a raised portion of the retaining lip to seats  54  defined by the retaining lip upper surface. A resilient radial extension  34  of the cartridge grommet  30  biases the cartridge  10  away from the base component  40  so that the seated retention tabs  24  resist unintended counterclockwise rotation of the cartridge  10  relative to the base. 
     In accordance with an aspect of the present invention, the retainer  44  defines lip portions  70  having an inward-facing profile including radially inward projecting protrusions  56  corresponding to the location of each inwardly displaced segment  22  of the roll seam  16  relative to the retention tabs  24  (the location of which correspond to the axial slots  51  separating the retaining lip portions  70 ). The axial slots  51  and lip portions  70  with protrusions  56  code the base component  40  for a filter cartridge such as cartridge  10  with a roll seam having a compatible pattern of retention tabs  24  and inwardly displaced segments  22 . The roll seam  16  of a compatible filter cartridge can pass the retaining lip portions  70 , permitting complete axial reception of the cartridge housing first section  12  into the receptacle  47  so that subsequent rotation of the cartridge mounts the cartridge to the base. An incompatible cartridge (lacking, for example, the requisite inwardly displaced segments  22 ) is blocked from axial reception and cannot be mounted to the coded base. 
       FIGS. 12 and 13  illustrate a second representative embodiment of a base component  80  configured to receive a cartridge illustrated in  FIGS. 1 -5 . This form of filter base comprises a cast or molded component  80  with a cylindrical wall  92  defining a receptacle  87  into which the housing first section  12  of the cartridge is axially receivable. The cartridge is retained to the base by a collar  100  (illustrated in  FIGS. 14 and 15 ) that engages the peripheral roll seam  16 . In accordance with an aspect of the present invention, the lip  82  of the wall  92  is provided with a sectional configuration complementary to the annular space  20  defined between the cartridge housing first section  12  and the roll seam  16 . Radial outward projections  84  of the lip correspond to the location and outward radial displacement of the retention tabs  24 . The base component  80  may be cast with the lip  82  having locations  86  where the lip is thinned or notched to accommodate inwardly displaced segments  22  of the cartridge roll seam  16 . Alternatively, lip material may be removed after production of the base component  80 , such as by machining the lip at locations  86 . 
     The collar  100  includes an inward projecting thread  108  configured to engage an outward projecting thread  88  on the base component  80 . Rotation of the collar  100  relative to the base component  80  causes the collar thread  108  to ride the base thread  88 , bringing the collar retaining lip  102  to bear against the radially projecting roll seam  16  of the cartridge  10 . A spring (not shown) in the base receptacle  87  biases the cartridge  10  and collar  100  away from the base component to maintain the collar in a locked position over the end of the base thread  88 . This mounting system requires that the axially projecting lip  82  of the base component be received in the annular space  20  with room for axial movement to accommodate compression and release of the spring as the collar thread  108  rides up and over the thread  88  of the base. A rigid abutment of the cartridge roll seam  16  against the lip  82  of the base that prevents the necessary axial movement of the cartridge  10  relative to the base component  80  will prevent complete rotation of the collar  100  to its locked position. 
     The lip  102  of the collar  100  includes a plurality of locations  103  where the lip and adjacent structure is recessed or lip material is removed to accommodate the shape  13  (an outward deflection best seen in  FIG. 1 ) of the cartridge housing second section  14  adjacent the outward deformation of the roll seam  16  for each retention tab  24 . In the illustrated embodiment, the collar is provided with six locations  103  where lip material is removed. The six locations  103  correspond to the six possible engaged positions of the collar  100  relative to the base component  80  and the received filter cartridge  10 . The outward deflections of the housing second section fit into three of the six locations, further enhancing the security of the collar  100  in its locked position relative to the cartridge  10  and the base component  80  by resisting unintentional reverse rotation of the collar. 
     A filter cartridge lacking outward deformations  24  of the roll seam  16  complementary to the outward projections  84  on the axially projecting lip  82  of the base component  80  will be blocked from axial reception and mating with the base. Similarly, filter cartridges including inward deformations of the roll seam will be rejected by a base whose axially projecting lip  82  does not include locations  86  where lip material has been removed to accommodate them. By axial reception and mating with the base, it is meant that the grommet  30  carried by the housing first section  12  fully engages the axial conduit  88  of the base component and the lip  82  of the base is received in the annular space  20  of the cartridge with room to move axially during rotation of the collar  100  to its locked position. Thus, the configuration of the axially projecting lip  82  forms a component of a cartridge compatibility matrix that codes the base for a cartridge having a particular shape of annular space  20  (as defined by deformations  24 ,  22  of the roll seam). 
     A further aspect of the present invention contemplates a filter cartridge compatibility matrix comprising the roll seam retention tabs  24  and inward displaced segments  22  as described above and further including radial protrusions  28  of the cartridge housing section first end  12 . In the first embodiment of a filter base component  40 , a ring (not shown) is keyed to the base component to define an entrance to the receptacle  47 . The ring includes openings that allow axial passage of the radial protrusions  28  of the housing first section  12 . Once the radial protrusions  28  are axially past the ring, the receptacle  47  of the base component  40  permits rotation of the cartridge relative to the base. Radial protrusions  28  of the housing first section  12  may be used as an additional component of the cartridge compatibility matrix. The radial protrusions may also be employed to ensure a particular installed orientation of the cartridge  10  relative to the base component  40 . 
     The inside surface of the wall  92  defining the receptacle  87  of the second embodiment of a filter base component  80  may include axial tracks (not shown) complementary to the pattern of radial protrusions from the cartridge housing first section  12 . The tracks may be molded and/or machined on the inner surface of the receptacle of the base component  80 . A filter cartridge including an incompatible pattern of radial protrusions will be blocked from axial reception into the receptacle  87 . In combination, the configuration of the filter cartridge roll seam  16  and received housing first section  12  can be used to ensure filter compatibility and a particular installed configuration of the filter cartridge  10  relative to the base component  80 . 
     While preferred embodiments of the present invention have been set forth for the purposes of illustration, the foregoing descriptions should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.