Patent Publication Number: US-7217169-B1

Title: Dimensionally stable flying disc toy construction

Description:
FIELD OF THE INVENTION 
   This invention relates to flying toys and more particularly to a dimensionally stable flying disc toy. 
   BACKGROUND OF THE INVENTION 
   Several disc shaped flying toys have been previously proposed as described, for example, in the following patents: Des. 329,121; U.S. Pat. Nos. 4,516,947; 3,359,678; 3,571,811; 4,212,131; and 4,378,653. 
   Flying toys of this kind have two general purposes; the entertainment of people and dogs, and to serve as an advertising medium. However, in manufacturing prior products of this kind, certain problems were encountered. The products were difficult to stack so that when put on top of one another for placement in boxes they did not form a stable stack. This made handling and packaging difficult and reduced the number of discs that could be placed in each box. In addition, when the discs were hot following removal from the forming dies, they were subject to distortion or warpage. Prior to developing the present invention, several flat tables were tried to support the hot discs just removed from molding dies in an attempt to allow them to harden without distortion. Placing them on the tables was time consuming and labor intensive. Advertising material printed on prior discs was also often of non-uniform or of uneven quality due to the surface distortion previously encountered. 
   In view of these and other deficiencies of the prior art, it is one object of the present invention to provide a flying disc toy of the type described that can be made dimensionally distortion free to thereby enhance flight characteristics and prevent printing problems. 
   Another object is to provide a flying disc toy having a distortion resistant feature for stabilizing the dimensions of the toy while at the same time maintaining or enhancing its aerodynamic flight characteristics. 
   Another object of the invention is to provide a flying disc toy that has a substantially uniform cross-sectional thickness throughout without enlarged or thickened portions which require additional resin. 
   Another object is to find a way to enable a toy of the type described to be removed from molds in a hot condition and be self-regulating with respect to maintaining dimensions and preventing distortion during the cooling process. 
   Yet another object of the invention is to provide an improved flying disc toy that requires no supporting fixtures during the cooling step after being withdrawn from molding dies and wherein a smaller carton than previously required can be used for the same number of discs. 
   These and other more detailed and specific objects of the present invention will be better understood by reference to the following Figures and detailed description which illustrate by way of example but a few of the various forms of the invention within the scope of the appended claims. 

   
     A BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  is a perspective view of the invention as seen from above. 
       FIG. 2  is a vertical cross sectional view of two disc toys in accordance with the invention on a larger scale than in  FIG. 1  as seen just before being placed together in a stack. 
       FIG. 3  is a view similar to  FIG. 2  showing two of the discs in a stack. 
       FIG. 4  is a partial top plan view of the invention. 
       FIG. 5  is a diagrammatic central cross-sectional view of the upper half of a mold that can be used for forming discs in accordance with the invention. 
   

   BRIEF SUMMARY OF THE INVENTION 
   Briefly, the invention provides a flying disc toy formed from plastic resin which includes a circular central body portion surrounded by a circular rim that has a stair-step cross-sectional configuration. The rim includes an upper step and a lower step that extends outwardly therefrom. Each step has a circular horizontal tread portion and an upright annular riser portion at right angles to one another. An inner surface of the lower riser is dimensioned to form a sliding fit over an outer surface of the upper riser of a similar disc that is positioned beneath it when the discs are placed in a stack. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The Figures illustrate by way of example a flying disc toy indicated generally by the numeral  10  which is formed from plastic resin, e.g., polyethylene or polypropylene having a flat circular center section  14  with a circular, downwardly inclined frustoconical apron portion  12  that intersects the center section  14  along a circular line  11 . The central body portion of the disc  10  comprises the inclined apron  12  and the flat section  14 . Surrounding the central body portion  12 ,  14  at the edge of the apron  14  is a rim  18  that can be thought of as having a stair-step cross-sectional configuration which has been found effective in rigidifying the rim as well as the entire disc. The wall of the disc typically has a thickness of about 1/16 inch and is of uniform thickness throughout, including the rim  18 . The upper step includes a circular tread portion  16  and an upright annular riser portion  20 . The lower step includes a circular tread portion  22  and an upright annular riser portion  26  that intersects along a shoulder defined by an edge  23 . The outer surface of the lower riser  26  converges centrally at  24  toward the bottom or free edge of the rim  18 . The entire structure of the disc is strengthened and rigidified by the steps which, as seen in  FIGS. 2 and 3 , act somewhat like two rigid angle irons connected together to resist bending in two mutually perpendicular directions. The under surface of the lower tread  22  forms an internal ledge  28 . The inner surface of the upper tread is indicated at  30 . It can be seen that the outside surface of the riser  20  is dimensioned slightly smaller than the inside surface  32  of the lower riser  26 . In this way each of the lower risers is dimensioned to form a sliding fit over an outer surface of one of the upper risers  20  thus enabling the flying disc toys to be placed in a stable stack, i.e., one in which the discs are recessed, i.e., telescoped into one another. The resulting stack does not wobble and the stack can therefore be handled and packaged easily. When handled, the stack acts almost as a pillar with internal structural strength. Each riser is at least about ⅛ of an inch in height to about 3/16 of an inch in height and most preferably about ¼ of an inch or more in height. It can also be seen in  FIG. 3  that the lower edge of the rim is configured and dimensioned to fit into a right angle intersection between the outer surface of the upper riser  20  and the upper surface of the lower tread  22 . When assembled the discs form a stable stack and have very good flight characteristics. 
   It was found that cooling tables previously used could be eliminated with the present invention and that the hot freshly molded discs could be removed from the molds and immediately placed in a stack ( FIG. 3 ) of, say, a dozen discs and the entire stack inserted into a shipping carton with a single movement. The stacked product was found to be dimensionally self-stabilizing in the sense that dimensions were accurately maintained without distortion so as to thereby preserve excellent aerodynamic flight qualities and eliminate the problem of non-uniform printing caused by distortions that were previously encountered. Thus the invention enables the hot stacking of the discs immediately after removal from the molds to harden the discs without distortion. It will be noted that the wall thickness of the rim  18  including the steps is substantially uniform throughout, the same as the rest of the disc. It is contemplated that the term “substantially uniform” herein includes variations such as the difference in thickness of the lower riser  26 . 
   It is important that the rim, which includes the steps, either maintains or enhances the aerodynamic flight characteristics of the disc. It was found that the invention exhibits excellent flight characteristics. It is theorized that the shoulder  23  may help to divide the streamlines as air passes around the upper and lower edges of the rim during flight. In addition, the two steps in the rim area provide extra vertical and horizontal surfaces which promote stability during flight. The invention also uses a minimum of resin and does not require thickened portions for stacking which would increase production costs because of the extra resin required. 
   As an alternative to screen printing, the top of the discs can be engraved with advertising material or other markings as shown in  FIG. 5 .  FIG. 5  illustrates diagrammatically the upper half of one preferred form of molding die that can be used to form the present invention. The upper half of the mold indicated by the numeral  50  includes a lower molding surface  52  that is shaped to mold the top of the disc  10 . The lower half of the mold is indicated generally at  54 . At the center of the upper half  50  of the mold is a removable circular and replaceable molding insert  56 . The insert  56  is engraved on its lower surface as shown at  58  to form letters, numbers, or other indicia for advertising or other purposes in the top of the disc  10 . When a different advertising text is required, the insert  56  is simply removed and replaced with a similar insert  56  having a different engraved message  58  thereby making advertising changes for different customers simpler and less expensive. 
   Many variations of the present invention within the scope of the appended claims will be apparent to those skilled in the art once the principles described herein are understood.