Abstract:
An internal support for an air filter includes a helical member which is shaped and dimensioned to fit against the inside surface of the air filter to provide structural support which prevents the air filter from inwardly collapsing. In another embodiment of the invention, a plurality of support rings are installed in spaced apart parallel relationship inside the air filter.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims the filing benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 60/586,592, filed Jul. 9, 2004, which is included herein by reference. 

   TECHNICAL FIELD 
   The present invention pertains generally to air filters, and more particularly to an inner support for cylindrical and conical air filters which prevents the air filters from collapsing. 
   BACKGROUND OF THE INVENTION 
   Air filters for heavy-duty transportation applications and also various internal combustion engines are designed to protect engines by forcing intake air to pass though a filtration process prior to entering the engine chamber. This is accomplished by forcing or sucking air through a pleated media air filter with a specific pass through efficiency prior to entering the engine chamber. This process allows for air intake into the engine chamber while preventing particulates from entering the engine. Air filtration efficiency is measured in terms of air flow, dust holding capacity, restriction, and final efficiency which is typically measured by amount of duct fed verses amount of duct blocked by the filter. 
   Existing air filtration products for transportation applications come in various shapes, sizes, number of pleats and specific efficiencies. The most prevalent air filter shapes for transportation applications are frustoconical and cylindrical. Cylindrical and frustoconical filters consist of pleated layers of filter media (usually cotton), wire mesh, and an inner support layer made up expanded metal bound together in polymer composite on either ends or with metal end caps. The inner support layer is required to prevent inward collapse of the filter unit during both storage and use. Currently in the vast majority of cylindrical and frustoconical air filters the inner support layer is made up of expanded metal, which greatly increases air resistance. The existing expanded metal inner support solution presents greater surface area for air to have to pass though. This prevents maximum air intake, which is a factor in greater engine performance, while proving no considerable advantage for filter efficiency. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is directed to an alternative solution to prevent filter collapse. The present invention replaces the existing expanded metal inner support layer with a streamlined method of inner support. In the present invention a helical (spiral shaped) inner support is installed on the inside of the filter media. The support provides radial support and prevents the filter from inwardly collapsing from the inward flow of air. The present invention provides a sizeable advantage for air filtration applications, provides the required structural support to prevent collapse, and presents minimal surface area thereby allowing maximum engine air intake. The result is higher engine performance with consistent engine protection and superior structural support. In another embodiment of the invention, a plurality of spaced apart support rings are installed on the inside of the filter media. 
   In accordance with a preferred embodiment of the invention, a support for an air filter includes a helical member which is shaped and dimensioned to fit against the inside surface of the air filter to provide structural support and prevent the air filter from inwardly collapsing. 
   In accordance with an aspect of the invention, the helical member is fabricated from spring steel or some other resilient material. 
   In accordance with another aspect of the invention, the helical member is fixedly attached to the inside surface of the air filter with a bonding agent. 
   In accordance with another aspect of the invention, the helical member has one of (1) a tapered shape, and (2) a cylindrical shape. 
   In accordance with another embodiment of the invention, the support comprises a plurality of ring members which are shaped and dimensioned to fit against the inside surface of the air filter in spaced apart relationship to prevent the air filter from inwardly collapsing. 
   Other aspects of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation view of a prior art frustoconical air filter; 
       FIG. 2  is an end view of the prior art frustoconical air filter; 
       FIG. 3  is an enlarged cross sectional view along line  3 - 3  of  FIG. 1 ; 
       FIG. 4  is a side elevation view of a support for an air filter in accordance with the present invention; 
       FIG. 5  is a breakaway side elevation view of the support of  FIG. 4  inserted inside the prior art frustoconical air filter; 
       FIG. 6  is an end view of the support inserted inside the prior art frustoconical air filter; 
       FIG. 7  is a side elevation view of a prior art cylindrical air filter; 
       FIG. 8  is an end view of the prior art cylindrical air filter; 
       FIG. 9  is a side elevation view of a second support for an air filter in accordance with the present invention; 
       FIG. 10  is a breakaway side elevation view of the support of  FIG. 9  inserted inside the prior art cylindrical air filter; 
       FIG. 11  is a top plan view of a second embodiment support for and air filter; 
       FIG. 12  is a side elevation view of the second embodiment support; 
       FIG. 13  is a breakaway side elevation view of the second embodiment support inserted inside the prior art frustoconical air filter; and, 
       FIG. 14  is a breakaway side elevation view of the second embodiment support inserted inside the prior art cylindrical air filter. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring initially to  FIGS. 1 and 2 , there are illustrated side elevation and end views respectively of a prior art frustoconical air filter, generally designated as  500 . Frustoconical air filter  500  is a frustum of a cone and includes a body comprised of a plurality of air filter pleats  502  which are arranged in circular relationship. The plurality of pleats  502  define an outside surface  504  and an opposite inside surface  506 . In use, air travels through air filter  500  from the outside surface  504  to the inside surface  506 . Frustoconical air filter  500  has a central axis  508 . 
     FIG. 3  is an enlarged cross sectional view along line  3 - 3  of  FIG. 1  showing pleats  502 , outside surface  504  and inside surface  506 . 
   Now referring to  FIG. 4 , there is illustrated a side elevation view of a support for an air filter in accordance with the present invention, generally designated as  20 . Support  20  includes a helical member  22  which is shaped and dimensioned to fit closely against inside surface  506  of cylindrical air filter  500  providing support thereto and thereby preventing cylindrical air filter  500  from inwardly collapsing. In the shown embodiment helical member  22  has a tapered shape to conform to the tapered inside surface  506  of frustoconical air filter  500 . Helical member  22  has a central axis  24 , and is fabricated from spring steel or any other material with sufficient strength to keep filter  500  from inwardly collapsing. 
     FIG. 5  is a breakaway side elevation view of support  20  inserted inside prior art frustoconical air filter  500 , and  FIG. 6  is an end view of support  20  inserted inside prior art frustoconical air filter  500 . It is noted that in  FIGS. 5 and 6 , pleats  502  have been omitted for clarity. Support  20  is inserted into frustoconical air filter  500  such that central axes  508  and  24  are co-linear, and so that support  20  closely fits against inside surface  506  of frustoconical air filter  500 . In the shown embodiment helical member  22  is fixedly attached to inside surface  506  of frustoconical air filter  500 . The attachment is effected by a bonding agent  26  (such as an epoxy, a polymer, an adhesive or the like) which fixedly attaches helical member  20  to inside surface  506  of the frustoconical air filter  500 . In the shown embodiment, helical member  22  has a length, and bonding agent  26  is placed at periodic intervals along the length of helical member  22 . 
   Now referring to  FIGS. 7 and 8 , there are illustrated side elevation and end views respectively of a prior art cylindrical air filter, generally designated as  600 . As with frustoconical air filter  500 , cylindrical air filter  600  includes a body comprised of a plurality of air filter pleats  602  which are arranged in circular relationship. The plurality of pleats  602  define an outside surface  604  and an opposite inside surface  606 . In use, air travels through air filter  600  from the outside surface  604  to the inside surface  606 . Cylindrical air filter  600  has a central axis  608 . 
   Now referring to  FIG. 9 , there is illustrated a side elevation view of a second support for an air filter in accordance with the present invention, generally designated as  40 . Support  40  includes a helical member  42  which is shaped and dimensioned to fit closely against inside surface  606  of cylindrical air filter  600  providing support thereto and thereby preventing cylindrical air filter  600  from inwardly collapsing. In the shown embodiment helical member  42  has a cylindrical shape to conform to the inside surface  606  of cylindrical air filter  600 . Helical member  42  has a central axis  44 , and is fabricated from spring steel or some other resilient material. 
     FIG. 10  is a breakaway side elevation view of support  40  inserted inside prior art cylindrical air filter  600 . It is noted that pleats  602  have been omitted for clarity. Support  40  is inserted into cylindrical air filter  600  such that central axes  608  and  44  are co-linear, and so that support  40  closely fits against inside surface  606  of cylindrical air filter  600 . In the shown embodiment helical member  42  is not fixedly attached to inside surface  606  of cylindrical air filter  600 , but rather is simply placed inside cylindrical air filter  600 . 
   Now referring to  FIGS. 11 and 12 , there are illustrated top plan and side elevation view respectively of a second embodiment support for an air filter, generally designated as  60 . Support  60  comprises a plurality of ring members  62  which are shaped and dimensioned to fit against the inside surface of the air filter in spaced apart parallel relationship, thereby preventing the air filter from inwardly collapsing. Ring members  62  have a central axis  64 . As with supports  20  and  40 , support  60  is fabricated from spring steel or some other suitable material. 
     FIG. 13  is a breakaway side elevation view of support  60  inserted inside prior art frustoconical air filter  500 . It is noted that pleats  502  have been omitted for clarity (refer to  FIG. 1 ). A plurality of ring members  62  are fixedly attached to inside surface  506  of the air filter  500 . The plurality of ring members  62  reside in parallel spaced apart relationship along axes  508  and  64 . Supports  60  are inserted into frustoconical air filter  500  such that central axes  508  and  64  are co-linear, and so that supports  60  closely fits against inside surface  506  of frustoconical air filter  500 . In the shown embodiment ring members  62  are fixedly attached to inside surface  506  of frustoconical air filter  500 . The attachment is effected by a bonding agent  26  (such as an epoxy, a polymer, an adhesive or the like) which fixedly attaches ring members  62  to inside surface  506  of the frustoconical air filter  500 . It may be appreciated that for use with a frustoconical air filter, each ring member  62  must have a different diameter. 
     FIG. 14  is a breakaway side elevation view of the second embodiment support  60  inserted inside prior art cylindrical air filter  600 . It is noted that pleats  502  are deleted for clarity (refer to  FIG. 1 ). A plurality of ring members  62  are fixedly attached to inside surface  606  of the air filter  600 . The plurality of ring members  62  reside in parallel spaced apart relationship along axes  608  and  64 . Supports  60  are inserted into cylindrical air filter  600  such that central axes  608  and  64  are co-linear, and so that supports  60  closely fits against inside surface  606  of cylindrical air filter  600 . In the shown embodiment ring members  62  are fixedly attached to inside surface  606  of cylindrical air filter  600 . The attachment is effected by a bonding agent  26  (such as an epoxy, a polymer, an adhesive or the like) which fixedly attaches ring members  62  to inside surface  606  of the cylindrical air filter  500 . It may be appreciated that for use with a cylindrical air filter, each ring member  62  must have the same diameter. 
   The preferred embodiments of the invention described herein are exemplary and numerous modifications, variations, and rearrangements can be readily envisioned to achieve an equivalent result, all of which are intended to be embraced within the scope of the appended claims.