Patent Document

BACKGROUND 
     1. Field of Invention 
     This invention relates to the field of metal founding, and more specifically to an apertured strainer means for separating unwanted components from casting material. 
     2. Description of Related Art 
     Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term “sand casting” can also refer to an object produced via the sand casting process. Specialized factories called foundries produce sand castings. Production of over 70% of all metal parts occurs via a sand casting process such as the DISAMATIC process. 
     High-volume foundries typically use vertical molding processes such as the DISAMATIC process. Molds form a line allowing pouring of castings one after another. The process blows a molding sand mixture into a molding chamber using compressed air. The process then squeezes the molding sand between patterned plates, each of which ultimately forms half of the pattern of the sand mold. Two sand molds pushed together form a complete internal sand cavity that receives the molten metal. 
     After squeezing, one of the chamber plates, a swing plate, swings open and the opposite plate, a ram plate, pushes the finished sand mold onto a conveyor. If desired, the process inserts cores into the sand cavity to form holes and recesses in the finished part. The cycle repeats until a chain of finished molds butt up to each other on the conveyor. 
     During this process, molten metal pours into sand cavities from a receptacle known in the art as a “pour cup” located on the top of each mold and positioned above a channel in the sand mold called the sprue. An automated device called a filter setter places the filter between the pour cup and the sprue inlet. The filter setter moves the filter into position and then injects the filter into the sand mold. The filter print is the area in the sand into which the filter inserts. 
     It is desirable to decrease the size of the filter print because the filter print and channels entirely fill with metal during the casting process. Metal left behind in the sprue, channels and filter print is excess metal, requiring removal from the part and repurposing. 
     It is a problem known in the art that repurposing metal recovered from the sprue, channels and filter print is very costly. An important component of a foundry&#39;s profitability is its ability to reduce the amount of repurposed metal and the effective “yield” of the metal that goes into the finished part. If a foundry is able to reduce the amount size of a sprue, channels and filter print by 10%, this could increase foundry yield by 2% to 5%. 
     There several problems associated with filters known in the art. Ceramic and silica filters must be carefully primed or they fracture and introduce fragments in the casting. Ceramic filters are large, requiring correspondingly large filter setters to hold them in place. Ceramic filters are also expensive. Custom sizes and shapes require special manufacturing, making them impractical for small production runs. 
     One solution is to replace ceramic filters with cloth or mesh filters. Previous attempts to use cloth filters failed because filter setters could not hold the filters in place or because the sand compromised parts used for clamping or releasing the filters. For example, sand can clog or compromise springs and ball bearings capable of securing and quickly releasing the filter. Additionally, ball bearing and spring devices known in the art did not sufficiently support the filter during insertion, resulting in incorrect filter positioning or entanglement with other parts before ejection. 
     It is desirable to provide a filter setter capable of holding a cloth filter. 
     It is further desirable to provide a filter setter with an increased resistance to compromise by sand. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment, a filter setter apparatus includes a housing, an upper jaw, and a lower jaw. The housing includes a plurality of upper jaw attachment bores extending from a top surface of an overhang to a bottom surface of the overhang. The housing also includes a plurality of lower jaw attachment bores extending from a front side to a back side. 
     The upper jaw has the shape of a rectangular bar with a plurality of upper jaw overlaps depending from either side of the upper jaw. The upper jaw includes a plurality of upper attachment bores. The upper jaw has a mass causing a gravitational force acting on the upper jaw to clamp a filter inserted between the upper jaw and the lower jaw. The upper jaw is removably connected to the housing by a plurality of upper jaw shoulder bolts extending between the plurality of upper jaw attachment bores and the plurality of upper attachment bores. 
     The lower jaw includes a plurality of lower attachment bores. The lower jaw is removably connected to the housing by a plurality of lower jaw shoulder bolt fasteners extending between the plurality of lower jaw attachment bores and the plurality of lower attachment bores. The upper jaw partially encloses the lower jaw between the plurality of upper jaw overlaps. 
     In accordance with another embodiment, a filter setter system incorporates the above housing with a plurality of the above upper jaws and a plurality of the above lower jaws. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 a  and 1 b    illustrate front and left side views, respectively, of an assembled filter setter. 
         FIGS. 2 a -2 c    illustrate perspective, front and top views, respectively, of a housing of the filter setter. 
         FIGS. 3 a -3 c    illustrate perspective, front and bottom views, respectively, of an upper jaw of the filter setter. 
         FIGS. 4 a -4 c    illustrate perspective, front and top views, respectively, of a lower jaw of the filter setter. 
     
    
    
     TERMS OF ART 
     As used herein, the term “shoulder bolt” means a bolt having an unthreaded section between bolt head and bolt thread. 
     DETAILED DESCRIPTION OF INVENTION 
     For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of a filter setter, only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent elements may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. 
     It should be understood that the drawings are not necessarily to scale. Instead, emphasis has been placed upon illustrating the principles of the invention. Like reference numerals in the various drawings refer to identical or nearly identical structural elements. 
     Moreover, the terms “about,” “substantially” or “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. 
       FIGS. 1 a  and 1 b    illustrate front and left side views, respectively, of an assembled filter setter  100 . Filter setter  100  includes a housing  10 , an upper jaw  20  and a lower jaw  30 . In use, as shown in  FIG. 1 b   , a cloth filter  40  lies between upper jaw  20  and lower jaw  30 . Cloth filter  40  remains in position during movement of filter setter  100  due to the effect of gravity on the mass of upper jaw  20 . Materials used to construct housing  10 , upper jaw  20  and lower jaw  30  may include any material capable of withstanding the high temperatures of the founding process and dense enough to provide an effective mass to upper jaw  20 . Such materials may include hardened steel. 
     Housing  10  includes ejector aperture hole  11 , threaded ejector bores  12   a  and  12   b,  upper jaw attachment bores  13   a  and  13   b,  housing attachment bores  14   a  and  14   b,  front side  15  and overhang  16 . Ejector aperture hole  11  allows an ejection mechanism such as a Bimba® ejection cylinder to expel cloth filter  40  from filter setter  100 . Threaded ejector bores  12   a  and  12   b  permit removable attachment of such an ejection mechanism to housing  11 . Housing  10  has dimensions of approximately 4 inches long, 2 inches high, and 1 inch wide at its widest point. 
     Upper jaw attachment bores  13   a  and  13   b  are smooth bores that run from the top of housing  10  to the bottom of overhang  16 . Upper jaw attachment bores  13   a  and  13   b  allow removable attachment of upper jaw  20  to overhang  16  so that upper jaw  20  hangs parallel to front side  15 . Housing attachment bores  14   a  and  14   b  permit removable attachment of housing  10  to another piece of foundry equipment using fasteners such as, but not limited to bolts, screws, locking bolts, locking screws, or any other fastening means known in the art (not shown). 
     Upper jaw  20  includes upper attachment bores  21   a  and  21   b,  upper jaw shoulder bolts  22   a  and  22   b,  upper leading edge  23 , upper jaw overlaps  24   a  and  24   b  and upper ejector aperture bore arch  25 . In the exemplary embodiment, because upper jaw  20  attaches to overhang  16 , upper jaw  20  has a depth no greater than the depth of overhang  16 . Furthermore, the width of upper jaw  20  is no greater than the width of housing  10 . 
     Upper attachment bores  21   a  and  21   b  are threaded blind bores in line with upper jaw attachment bores  13   a  and  13   b,  respectively. Upper jaw shoulder bolts  22   a  and  22   b  pass through upper jaw attachment bores  13   a  and  13   b,  respectively, and into upper attachment bores  21   a  and  21   b,  again respectively, allowing variable and removable connection of housing  10  and upper jaw  20 . Because upper jaw attachment bores  13   a  and  13   b  are smooth bores, upper jaw shoulder bolts  22   a  and  22   b  can slide within upper jaw attachment bores  13   a  and  13   b,  thereby permitting upper jaw  20  to raise and lower with respect to overhang  16 . 
     Upper leading edge  23  provides easier insertion of cloth filter  40  between upper jaw  20  and lower jaw  30  by guiding cloth filter  40  between upper jaw  20  and lower jaw  30 . In the exemplary embodiment, upper leading edge  23  is a chamfer having an angle of approximately 30 degrees to approximately 45 degrees. In another embodiment, upper leading edge  23  is rounded. In the exemplary embodiment, upper jaw  20  has the shape of a rectangular bar with two rectangular upper jaw overlaps  24   a  and  24   b  depending from either side. Upper jaw overlaps  24   a  and  24   b  prevent cloth filter  40  from moving from side to side when inserted between upper jaw  20  and lower jaw  30 . The distance between inner walls of upper jaw overlaps  24   a  and  24   b  is the maximum width of cloth filter  40 . 
     To accommodate wider or higher cloth filters  40 , a user may remove and replace upper jaw  20  with another upper jaw  20  having a different distance between inner walls of upper jaw overlaps  24   a  and  24   b.  If using a tall cloth filter  40 , the section of upper jaw  20  between upper jaw overlaps  24   a  and  24   b  may become too thin to provide sufficient mass to keep cloth filter  40  in position. In this case, increasing the height of upper jaw overlaps  24   a  and  24   b  may provide sufficient mass. Upper ejector aperture bore arch  25  is an arc corresponding to an upper circular segment of ejector aperture hole  11 . Upper ejector aperture bore arch  25  provides clearance for an ejection mechanism traveling through ejector aperture hole  11 . 
     Lower jaw  30  includes jaw locater bores  31   a  and  31   b,  lower attachment bores  32   a  and  32   b,  lower jaw shoulder bolt fasteners  33   a  and  33   b,  lower ejector aperture bore bow  34  and lower leading edge  35 . In the exemplary embodiment, because upper jaw  20  attaches to front side  15  beneath overhang  16  and upper jaw  20 , lower jaw  30  has a depth no greater than the depth of overhang  16  and upper jaw  20 . In the exemplary embodiment, because lower jaw  30  is bounded to either side by upper jaw overlaps  24   a  and  24   b,  lower jaw  30  has a width no greater than then distance between the inner walls of upper jaw overlaps  24   a  and  24   b.    
     Jaw locater bores  31   a  and  31   b  allow lower jaw  30  to receive guidance pins (not shown) attached to another piece of foundry equipment, thereby guiding placement of filter setter  100 . Lower jaw shoulder bolt fasteners  33   a  and  33   b  pass through lower attachment bores  32   a  and  32   b,  respectively, and into housing  10 , allowing removable connection of housing  10  and lower jaw  20 . Lower jaw shoulder bolt fasteners  33   a  and  33   b  may be, but are not limited to bolts, screws, locking bolts, locking screws, or any other fastening means known in the art. Because upper jaw overlaps  24   a  and  24   b  bound lower jaw  30  to either side, replacement of upper jaw  20  generally accompanies replacement of lower jaw  30 , to ensure adequately bounding and support of cloth filter  40 . 
     Lower ejector aperture bore bow  34  is an arc corresponding to a lower circular segment of ejector aperture hole  11 . Lower ejector aperture bore bow  34  provides clearance for an ejection mechanism traveling through ejector aperture hole  11 . Lower leading edge  35  provides easier insertion of cloth filter  40  between upper jaw  20  and lower jaw  30  by guiding cloth filter  40  between upper jaw  20  and lower jaw  30 . In the exemplary embodiment, lower leading edge  35  is a chamfer having an angle of approximately 30 degrees to approximately 45 degrees. In another embodiment, lower leading edge  35  is rounded. 
       FIGS. 2 a -2 c    illustrate perspective, front and top views, respectively, of housing  10  of filter setter  100 . As can be seen in  FIGS. 2 a   - 2   c,  housing  10  further includes a back side  17 , lower jaw locater pin bores  18   a  and  18   b  and lower jaw attachment bores  19   a  and  19   b.  Lower jaw locater pin bores  18   a  and  18   b  travel from back side  17  to front side  16 , and are in line with jaw locater bores  31   a  and  31   b , respectively. Lower jaw locater pin bores  18   a  and  18   b  allow housing  10  to receive guidance pins (not shown) attached to another piece of foundry equipment, thereby guiding placement of filter setter  100 . Lower jaw attachment bores  19   a  and  19   b  are bores in line with lower attachment bores  32   a  and  32   b,  respectively. Lower jaw shoulder bolt fasteners  33   a  and  33   b  pass through lower jaw attachment bores  19   a  and  19   b,  respectively, and into lower attachment bores  32   a  and  32   b,  again respectively, allowing removable connection of housing  10  and lower jaw  30 . 
       FIGS. 3 a -3 c    illustrate perspective, front and bottom views, respectively, of upper jaw  20  of filter setter  100 . 
       FIGS. 4 a -4 c    illustrate perspective, front and top views, respectively, of a lower jaw  30  of filter setter  100 . 
     In the exemplary embodiment, upper jaw  20  rests on lower jaw  30  when filter setter  100  is not in use. A space exists between overhang  16  and upper jaw  20 . When a user or mechanism inserts cloth filter  40  between upper jaw  20  and lower jaw  30 , upper jaw  20  rises and reduces the space between overhang  16  and upper jaw  20  until upper jaw  20  comes into contact with overhang  16 . Upper jaw  20  need not contact overhang  16  to retain cloth filter  40 . Gravity exerts a downward force, pushing down the mass of upper jaw  20 . If filter setter  100  briefly moves into a partially rotated or upside-down orientation, inertia will prevent movement of upper jaw  20 . After embedding cloth filter  40  in a mold, an ejection mechanism can eject cloth filter  40  from filter setter  100  to ensure that cloth filter  40  embedded in the mold. 
     In the exemplary embodiment, a user may remove one or both of upper jaw  20  and lower jaw  30 , and replace them with an upper jaw  20  having different dimensions and/or a lower jaw  30  having different dimensions. For example, a user could remove lower jaw  30  and replace it with another lower jaw  30  having a different height, allowing filter setter  100  to accommodate a higher cloth filter  40 . A user could remove upper jaw  20  and lower jaw  30 , and replace them with a wider lower jaw  30  and a correspondingly dimensioned upper jaw  20 . This new configuration would allow use of a wider cloth filter  40 . Various combinations of upper jaw  20  and lower jaw  30  can accommodate a wide variety of cloth filters  40  using the same housing  10  as a base.

Technology Category: b