Abstract:
A separate filter cartridge and latch release are used to replace a used filter cartridge in a filter assembly having a latch. In one example, the filter cartridge includes opposing end caps that are substantially the same as one another. The end caps have central holes. The filter cartridge is inserted into a filter assembly housing in which the latch prevents a cover from being installed onto a filter assembly housing until the latch is deactivated. The latch release is arranged relative to the filter cartridge to cooperate with the latch to enable the cover to be reattached to the filter assembly housing. The latch release includes tabs that align with features of the latch and extend through the central holes to cooperate with the latch. The latch release is removably secured to the cover and the filter cartridge.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to a filter cartridge and a method and apparatus for replacing the filter cartridge from a filter housing. Specifically, the invention includes a latch release that is used separately from the filter cartridge to enable installation of a new, replacement filter cartridge.  
         [0002]     Filter assemblies are used for many applications such as for various fluid systems of an automobile. The filter assemblies, for example, are used to filter fuel, air, oil and transmission fluid. Typical filter assemblies use many disposable components such as housings, valves and seals that add to the cost of the filter assembly. Furthermore, these components of the filter assembly should be properly disposed of to minimize the environmental impact. Disposal can be difficult and costly.  
         [0003]     It is desirable to reduce the cost and environmental impact associated with replacement of the filter assembly. One solution has been to provide a permanent filter housing that is mounted to a portion of the vehicle. The housing has a cover that is removable to receive a replacement filter cartridge. The filter cartridge typically only includes opposing end caps and a filter element retained between the end caps. The filter cartridge is replaced at desired intervals.  
         [0004]     Some filter assemblies using permanent housings incorporate a latch that prevents reinstallation of the cover unless a particular replacement filter cartridge is used. The particular filter cartridge uses two distinct end caps. The particular filter cartridge must be installed into the filter housing into a particular orientation. One end cap has features integrated with it that cooperates with the latch permitting the cover to be reinstalled.  
       SUMMARY OF THE INVENTION  
       [0005]     The invention relates to a filter cartridge and latch release that may be packaged with one another for use in replacing a used filter cartridge in a filter assembly. In one example embodiment, the filter cartridge includes opposing end caps that are substantially the same as one another. The end caps have central holes. The filter cartridge is inserted into a filter assembly housing, which includes a latch that prevents a cover from being installed onto the filter assembly housing over the filter cartridge until the latch is deactivated.  
         [0006]     The latch release, which is a separate component from the filter cartridge, is arranged relative to the filter cartridge to cooperate with the latch to enable the cover to be reattached to the filter assembly housing. The latch includes tabs that align with features of the latch and extend through the central hole of an exposed end cap to cooperate with the latch.  
         [0007]     These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a cross-sectional view of a filter assembly with an inventive filter cartridge and latch release, with a latch in an unlatched position.  
         [0009]      FIG. 2  is a cross-sectional view of a bypass valve and latch of the filter assembly shown in  FIG. 1  in the latched position.  
         [0010]      FIG. 3  is a top elevational view of the bypass valve and latch shown in  FIG. 2 .  
         [0011]      FIG. 4  is a bottom perspective view of the inventive filter cartridge and latch release.  
         [0012]      FIG. 5  is a top perspective view of the filter cartridge and latch release shown in  FIG. 4 .  
         [0013]      FIG. 6  is a cross-sectional view of the inventive latch release.  
         [0014]      FIG. 7  is an exploded perspective view of the filter assembly with the bypass valve and latch in the latched position shown in  FIG. 2  prior to installation of the inventive filter cartridge. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]     An example filter assembly  10  is shown in  FIG. 1  in cross-section. The filter assembly  10  includes a housing  12  having a body  14  providing a cavity  16 . A cover  18  is removably secured to the body  14  to provide access to the cavity  16  when desired. In the example shown, the cover  18  is threadingly secured to the body  14 . The cover  18  includes a feature at its exterior to facilitate removal of the cover  18  from the body  14 , such as a hexagonal protrusion for receiving a wrench.  
         [0016]     An inventive filter cartridge  20  is arranged within the cavity  16  for filtering a fluid flowing through the cavity  16 . The housing  12  includes an inlet side  22  and an outlet side  24  respectively arranged at an exterior and interior of the filter cartridge  20 . Fluid is provided to the inlet side  22  through an inlet  26  at a base of the body  14 . Fluid exits the outlet side  24  through an outlet  28  at the base of the body  14 . Arrows F indicate fluid flow through the filter assembly  10 . However, fluid flow may be the reverse of the direction indicated, and the inlet and outlet  26  and  28  may be provided elsewhere on the housing  12 .  
         [0017]     The housing  12  includes a center tube  30  extending through a central opening in the filter cartridge  20 . The center tube  30  is in fluid communication with the outlet side  24  and outlet  28 . The center tube  30  provides support for the filter cartridge  20 , as is known in the art, and may include apertures at various locations to permit fluid flow to an interior of the center tube  30 .  
         [0018]     A bypass valve  32  is slidably received by the center tube  30  and is movable along an axis A. The bypass valve  32  is urged to a closed position (shown in  FIG. 1 ) by a bypass valve spring  34 . The bypass valve  32  moves to an open position to permit fluid to flow from the inlet side  22  directly into the center tube  30  if the filter cartridge  20  becomes clogged. The bypass valve spring  34  has a spring rate selected to enable the bypass valve  32  to open at a predetermined pressure corresponding to a clogged filter cartridge  20 .  
         [0019]     A latch  36  is slidably received by the bypass valve  32  and center tube  30  and is movable along the axis A. The bypass valve spring  34  is supported between the bypass valve  32  and an upper portion of the latch  36 , which is known. The latch  36  is shown in an unlatched position in  FIG. 1 , which permits the cover  18  to be fully installed onto the body  14 .  
         [0020]     Referring to  FIGS. 1 and 2 , a latch spring  38  is arranged between a shoulder  42  of the center tube  30  and a head  44  of the latch  36 . The latch spring  38  biases the bypass valve  32  and latch  36  upward to a latched position, which is shown in  FIG. 2 . The bypass valve  32  includes downwardly depending first legs  46  that are arranged in alternating relationship to second legs  47  of the latch  36 . The center tube  30  includes a radially extending ledge  48 . The first legs  46  extend outward and into engagement with an inner surface  51  of the center tube  30  which is above the ledge  48 , as shown in  FIG. 2 . The latch  36  includes a radial flange  50  that is arranged radially inward of ends of the first legs  46  to urge the first legs  46  into engagement with the inner surface  51  when the bypass valve  32  and latch  36  are in the latched position. In the latched position, the bypass valve  32  is prevented from being inserted back into the center tube  30  unless the latch  36  is released, which will be discussed in more detail below.  
         [0021]     Referring to  FIG. 3 , an upper portion of the bypass valve  32  includes alternating apertures  52 . The latch  36  includes protrusions  54  that extend into the apertures  52 . Engagement and downward movement of the protrusions  54  moves the radial flange  50  out of engagement with the ends of the first legs  46  so that the first legs  46  disengage from inner surface  51  and are permitted to move inward and downward into the center tube  30 , past the ledge  48 , to the unlatched position.  
         [0022]     As shown in  FIGS. 4-6 , filter cartridge  20  includes end caps  56  that are substantially similar so that the filter cartridge may be inserted into the cavity  16  with either end cap  56  first. In the example shown, the end caps  56  are identical to one another. Both end caps  56  include large central holes  58  with a gasket  60  arranged about a circumference of the holes  58 . The gasket  60 , for example, is constructed from a felt material. The end caps  56  include a generally U-shaped cross-section, which is best seen in  FIG. 1 . A filter element  62  is retained between the end caps  56  in any suitable manner, for example, using an adhesive material, which is well known in the art.  
         [0023]     Referring to  FIGS. 4-6 , the inventive filter cartridge  20  cooperates with a separate latch release  40  that is used to engage the protrusions  54  to move the latch  36  axially downward and into the center tube  30 . The example latch release  40  is a disc-shaped body.  
         [0024]     The latch release  40  includes an inner annular flange  68  providing an opening  64  permitting fluid to flow from the inlet side  22  to the bypass valve  32 . An end  70  of the inner annular flange  68  engages a surface  72  of the bypass valve  32  to prevent fluid flow passed the bypass valve  32  when in the closed position.  
         [0025]     The latch release  40  also includes an outer annular flange  66  on the same side as the inner annular flange  68 . The outer annular flange  66  engages an inner wall  61  of the adjacent, exposed end cap  56  to provide a seal with the end cap  56 . The gasket  60  also seals with the end cap  56 . The inner wall  61  of the opposite end cap  56  engages an outer surface of the center tube  30  or another feature of the housing  12 , which is best shown in  FIG. 1 .  
         [0026]     The latch release  40  also includes multiple arcuate holes  82  to permit fluid flow past the latch release  40 .  
         [0027]     The latch release  40  includes tabs  74  extending from the latch release  40  on a side opposite the outer and inner annular flanges  66  and  68 , in the example shown, to engage the protrusions  54 . In the example shown, the tabs  74  extend radially outwardly from the inner annular flange  68  in a star-shaped configuration. However, the tabs  74  may be of any number and of any suitable configuration.  
         [0028]     In the example shown, the latch release  40  includes retaining members  76  that cooperate with the cover  18  to secure the latch release  40  to the cover  18 . The retaining members  76  are prongs that cooperate with an annular recess  80  of an aperture  78  in an underside of the cover  18 , which is shown in  FIGS. 1 and 7 . The latch release  40  may be snapped to the cover  18  using the retaining member  76  and annular recess  80 .  
         [0029]     In operation, the cover  18  is removed from the body  14  at a desired interval to provide access to the cavity  16  so that the filter cartridge  20  may be replaced. Once the used filter cartridge  20  is removed, the bypass valve  32  and latch  36  automatically extend to a latched position, as shown in  FIGS. 2 and 7 , under the biasing force of latch spring  38 . The inventive filter cartridge  20  is placed over the center tube  30  so that one end cap  56  is in sealing engagement with the outer surface  63 . Since the end caps  56  are the same, the inventive filter cartridge  20  may be inserted into the cavity  16  with either end cap  56  inserted first.  
         [0030]     Next, the latch release  40  is installed onto the exposed end cap  56 . The gasket  60  seals against the latch release  40  and the outer annular flange  66  seals against the inner walls  61  of the exposed end cap  56 . The latch release  40  is aligned so that the tabs  74  engage the protrusions  54 . Now, downward movement of the latch release  40  moves the latch  36  downward to disengage the radial flange  50  from the first legs  46 . The cover  18  can then be threadingly secured to the body  14 . The retaining members  76  will snap into engagement with the annular recess  80  upon complete installation of the cover  18  onto the body  14 . Subsequent removal of the cover  18  will allow removal of both the latch release  40  and the filter cartridge  20  from the cavity  16 .  
         [0031]     Alternatively, the latch release  40  can be installed onto the cover  18  and then the cover  18  can be threadingly secured to the body  14  after installation of the filter cartridge  20 . Rotation of the cover  18  will align the tabs  74  with the protrusions  54 . The tabs  74  will be retained within the apertures  52  thereby maintaining alignment with the protrusions  54  during additional rotation of the cover  18  during reinstallation.  
         [0032]     The latch release  40  and end caps  56  are preferably constructed from a plastic material capable of withstanding the fluid environment to which the latch release  40  and end caps  56  are exposed. The filter element  62  is preferably a pleated paper element. The latch release  40 , end caps  56  and filter element  62  can be easily disposed of, such as by low temperature incineration, in an environmentally friendly manner.  
         [0033]     The latch release  40  and filter cartridge  20  are preferably sold as a kit to customers. In instances when such a kit has already been used with the housing  12 , the old latch release  40  may be reused and the new latch release  40  may be recycled or vice versa.  
         [0034]     Although a preferred embodiment of this invention has been disclosed, a worker, of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention