A toy-building element

Abstract

A toy-building element for a toy-building system in which toy-building elements can be releasably coupled to one another using an interference fit between coupling studs of one toy-building element inserted in matching openings in another toy-building element. The toy-building element includes a body part with a top face, a bottom face and one or more flat sidewalls that extend around an outer periphery of the toy-building element, the one or more flat sidewalls at least partially define the interior of the toy-building element and the flat sidewalls extend between the top face and the bottom face with the sidewalls being connected to one another at right angles to form sharp corners, at least one cylindrical coupling stud extending at a given height from the top face, and at least one tubular projection extending inside the interior to the bottom face for forming at least one opening in the bottom face in which a coupling stud fits with the interference fit. The at least one projection is detached from the flat sidewalls. The at least one tubular projection includes four substantially flat contact walls extending perpendicularly to the bottom face, the four contact walls being arranged in a squared arrangement with each of the four contact walls arranged at a 45° angle with the side walls.

1 .- 12 . (canceled) 
     
     
         13 . A toy-building element for a toy-building system in which toy-building elements can be releasably coupled to one another using an interference fit between coupling studs of one toy-building element inserted in matching openings in another toy-building element, the toy-building element comprising:
 a body part with a top face, a bottom face and one or more flat sidewalls that extend around an outer periphery of the toy-building element,   the one or more flat sidewalls at least partially define said interior of said toy-building element and the flat sidewalls extend between the top face and the bottom face with the sidewalls being connected to one another at right angles to form sharp corners,   at least one cylindrical coupling stud extending at a given height from the top face, and   at least one tubular projection extending inside the interior to the bottom face for forming at least one opening in the bottom face in which a coupling stud fits with said interference fit, said at least one projection being detached from said flat sidewalls,   wherein said sides of said sidewalls facing the interior can be provided with contact ribs that extend from said bottom face towards said top face,   characterized in that:   the at least one tubular projection comprises four substantially flat contact walls extending perpendicularly to the bottom face, said four contact walls being arranged in a squared arrangement with each of the four contact walls arranged at a 45° angle with said side walls,   said four contact walls of a tubular projection are connected to one another to form a tube with a squared cross-sectional outline, and in that   a contact wall forms together with two sidewalls or with two contact ribs an opening in which a coupling stud fits with an interference fit with three contact lines and/or wherein a contact wall forms together with one sidewall or one contact rib and one contact wall of another tubular projection an opening in which a coupling stud fits with an interference fit with three contact lines.   
     
     
         14 . A toy-building element according to  claim 13 , wherein the four contact walls of one tubular projection together define an opening in which a coupling stud fits with an interference fit. 
     
     
         15 . A toy-building element according to  claim 13 , wherein said cross-sectional outline of said tube resembles or equals a rounded square, a square with rounded corners or a squircle. 
     
     
         16 . A toy-building element according to  claim 14 , provided with at least two of said tubes with neighboring tubes being interconnected with one another at opposing corners of said tubes concerned. 
     
     
         17 . A toy-building element according to  claim 16 , provided with at least two of said tubes with neighboring tubes being interconnected with one another at opposing corners of said tubes concerned and the other corners of said tubes are not interconnected with anything, wherein said wall thickness of said tubes concerned at said interconnected corners is reduced relative to said wall thickness of said other corners of said tubes concerned. 
     
     
         18 . A toy-building element according to  claim 17 , wherein said wall thickness of said tube is varied along said circumference of said tube in order to obtain a homogeneously distributed stress level in said tube when a stud is disposed in an opening bordering said tube concerned or in said tube concerned. 
     
     
         19 . A toy-building element according to  claim 17 , wherein said wall thickness of said tube is varied along said circumference of said tube in order to obtain resiliency against deformation by said insertion of a stud. 
     
     
         20 . A toy-building element according to  claim 18 , wherein said wall thickness along said circumference of said tube is higher at said corners of said tube and higher in said middle of said extent of said tube between corners and lower in said remaining circumferential extent of said tube. 
     
     
         21 . A toy-building element according to  claim 13 , wherein the at least one cylindrical coupling stud having a given outer diameter, and wherein said size of said gap between opposing contact walls of a tubular projection is slightly less than the diameter. 
     
     
         22 . A toy-building element according to  claim 13 , wherein said circular outline of said coupling studs is slightly larger than said opening between said contact walls and said side walls or said ribs on said inner side of said side walls. 
     
     
         23 . A method for manufacturing a toy-building element according to  claim 13 , wherein said method comprises injection molding said toy-building element in a mold that comprises at least two mold parts, where one of said two mold parts comprises a mold core, which shapes said inner faces of said toy-building element, and wherein said mold core comprises a recess to form said at least one tubular projection. 
     
     
         24 . A molding tool for the manufacture of a toy-building element according to  claim 13 , wherein said mold comprises at least two mold parts, where one of said mold parts comprises a mold core, which shapes said inner faces of said toy-building element, and wherein said mold core comprises a recess to form said at least one tubular projection.