Patent Publication Number: US-4545421-A

Title: Nonskid box studs

Description:
TECHNICAL FIELD 
     This invention relates to the art of casting, and in particular relates to the art of casting structures having supporting elements which are fused into a molded product. 
     BACKGROUND ART 
     It is known in the art of casting to provide a supporting element, a &#34;box stud&#34;, having upper and lower support plates connected by a bar-like separation element for being placed between form surfaces. Published German Patent Application No. 2,258,831 shows such a supporting element. 
     A prior-art supporting element is attached to the core surface by using nails which pass through perforations in upper or lower supporting plates. These nails are driven into the molding sand of the core and thus require a significant amount of labor. Furthermore, in practice it has been found that automatic nailing machines are not useful in this operation and that the nailing frequently damages the molding sand. 
     It is also known, for example, from published German Patent Application No. 2,923,702 that the supporting element can be glued to the front surface of a core. This type of supporting element suffers from the disadvantage that it cannot be placed on the core surface by an automatic setting machine because the elements become glued together in the feeder box of the automatic setting machine. Furthermore, coating with glue requires an additional step which adds expense to the operation. 
     It is also known to provide support plates with front faces having a plurality of concentric ribs of semi-circular cross section. The ribs are designed to extend into the molding sand to thereby increase the resistance to moving the supporting elements with respect to the core surface. This has not been successful, however, for several reasons. The supporting elements are small, light objects that do not effectively penetrate into the molding sand which has typically been soaked with furan resin. The distance between the outer extent of the ribs and the form surface is so small that liquid metal cannot flow between a support plate and the surface of the mole sand, thus producing an unsightly depression in the surface of the finished casting. The provision of the ribs also results in additional cost. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, a plurality of supporting elements are secured to each other by an interconnecting element. The supporting element includes two support plates and a separation element. In one embodiment, the interconnecting element is attached to the separation element which extends between upper and lower support plates. In a second embodiment, the interconnecting element is attached to an inner surface of one of the first and second support plates. The supporting elements and the interconnecting element are made of fusible material and are welded into the final casting. 
     The interconnecting element fixes the distances between adjacent supporting elements and preferably follows the contour of the core surfaces. The force required to support the casting plates is divided among the various supporting elements. Furthermore, the interconnecting element provides for positive fixation of the supporting elements to an uneven core surface and facilitates the correct positioning of the supporting elements. 
     In one embodiment, the interconnecting element comprises a closed loop. In a second embodiment, the interconnecting element is a strip having a plurality of openings with serrated edges. In other embodiments, the interconnecting element is a wire and a wire mesh. 
     An object of this invention is to provide supporting elements for spacing casting cores wherein the supporting elements are interconnected. 
     Another object of this invention is to provide interconnected spacing elements wherein the interconnecting element is bent to follow the contour of a casting core. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevation view of a plurality of supporting elements in accordance with the invention. 
     FIG. 2 is top view of the structure shown in FIG. 1. 
     FIG. 3 is elevation of a plurality of supporting elements wherein the interconnecting element is bent. 
     FIG. 3a is a modified form of the invention shown in FIG. 3. 
     FIG. 4 is a plan view of the invention as shown in FIG. 3. 
     FIG. 5 is a perspective of a casting core showing supporting elements interconnected in accordance with the invention. 
     FIG. 6 is a partial end view of upper and lower casting molds. 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     With reference to FIG. 1, a plurality of supporting elements 2 are shown. Each supporting element 2 includes an upper support plate 4 and a lower support plate 6. The upper and lower support plates are connected by a separation bar or shank 8. The supporting elements are placed between casting cores as is known in the art to provide separation of the cores. The elements 2 are interconnected by an interconnecting element 10 which is shown in FIG. 1 to be attached to the separation bars 8 approximately midway between upper and lower support plates 4, 6. 
     FIG. 2 shows a plan view of the structure shown in FIG. 1. In FIG. 2, selected ones of the upper support plates 4 have holes 12 therein for receiving nails to secure the supporting elements to the casting sand in the mold. In a preferred embodiment, the interconnecting element 10 has openings 14 therein, and the edges of these openings are alternatively serrated as illustrated at 16. Also, the outer edges of the interconnecting element 10 may be serrated as illustrated at 18. 
     FIGS. 3 and 3a show embodiments of the invention wherein the interconnecting element 10 has at least two portions which lie in respective, intersecting planes. This embodiment is particularly useful when the casting mold has a surface contour which requires the supporting elements 2 to lie in different planes. 
     In the embodiment shown in FIG. 3a, the interconnecting element 10 is connected to the bottom surfaces of upper support plates 4 instad of the shank 8. 
     FIG. 3 shows an embodiment similar to that shown in FIG. 3a. The interconnecting element 10 is bent to provide the reticulated form shown in the figure, and each corner 20, 22 includes a bead 24 to strengthen the corner bend. Closely spaced supporting elements may use common upper and lower support plates 4&#39; and 6&#39;. 
     FIG. 4 is a plan view of the embodiment shown in FIG. 3 and shows the interconnecting element 10 in the form of a closed loop having openings 14. Recesses 26 are formed in an edge of the interconnecting element 10. 
     FIG. 5 is a perspective view a casting mold 28 and shows a preferred manner of placing supporting elements 2 with respect to the mold 28 to provide a separation between lower mold 28 and an upper mold 30 (see FIG. 6). It is clear from FIG. 5 how the interconnecting element 10 greatly simplifies the placement of supporting elements 2. Formerly, it was necessary to secure each individual element to the casting mold. The invention allows the plurality of supporting elements to be easily located to thus reduce cost of manufacturing the element and the installation cost. 
     FIG. 6 is an end view of lower mold 28 and an upper mold 30 and shows the supporting elements 2 placed between the molds. The interconnecting element 10 preferably follows the contour of the inner surface of the molds so that it is always located between the mold surfaces. It is possible, as shown in FIG. 3a, for the interconnecting element 10 to be closely spaced from a surface of the mold. The interconnecting element is alternatively a strip, a wire, or a wire mesh. 
     It will be appreciated that a unique structure has been shown wherein the supporting elements are interconnected to facilitate the placement of a plurality of supporting elements in a casting mold. Modification of the invention within the scope of the appended claims will be apparent to those of skill in the art.