Abstract A construction toy including a splined shaft and a wheel element nonrotatably fitting thereon and retained by a spring ring which grips the shaft. A hub element is detachably secured to the wheel, with the spring occupying a recess between wheel and hub elements to limit their movement on the shaft. A. The Problem Small children playing with mechanical toy building sets often have difficulties in securing pinions, pulleys, discs and similar wheel elements on shafts when building vehicles or other mechanical devices. Fastening such wheel elements on the shafts generally requires the use of tools or accessories which are difficult to handle for small children. B. The Solution Two essential features are required for solving this problem, and the invention consists in the combination of these features: A. To provide a shaft having a noncircular cross section and wheel elements having a complementary hole, so as to enable the child to mount the wheels on the shaft by pushing them thereon from one end, thereby fixing the wheels on the shaft so as to prevent relative rotational movement. B. To provide a frictional fit between the shaft and the wheels so that axial displacement can only be effected by overcoming the friction therebetween. To this end a cylindrical recess is provided in the wheel element surrounding the central hole therein and an annular spring is located in the cylindrical recess in such a manner as to exert a radial pressure against the shaft, thereby increasing the frictional resistance against axial displacement of the wheels relatively to the shaft. The functioning of this spring is automatic and requires no skill or attention on the part of the user. C. The shaft may be tapered at one end, so as to facilitate the mounting of the wheels. D. The width of the cylindrical recess or cavity within the wheel is greater than the thickness of the spring to prevent the spring from being jammed within the cylindrical recess. E. The cylindrical cavity or recess is closed so as to totally enclose the annular spring by means of a hub element assembled with the side of the wheel.
In a toy building set, a wheel and shaft assembly comprising the combination of the following components made by injection molding of a thermoplastic material: a. A splined shaft element having a plurality of axially extending grooves forming ribs therebetween, said ribs having cylindrical outer surfaces coaxially disposed with respect to the shaft; b. An internally splined wheel element fitting the shaft element, so as to be slidably, but nonrotatably secured thereto, said wheel element comprising a disc-shaped member having at least one plane side face, a central bore in said plane side face defining a cylindrical recess in said discshaped member; c. An annular spring fitting into said cylindrical recess, the width of said annular spring being less than the depth of said cylindrical recess; and d. An internally splined hub element fitting the shaft element so as to be slidably, but nonrotatably mounted thereon adjacent the cylindrical recess in the disc-member, thereby defining a closed cylindrical cavity in said disc enclosing the said annular spring, said disc and hub elements being provided with means for mutually interlocking them, said spring being of a size such that, when said wheel element, spring and hub element are mounted on said shaft element, said spring exerts a radial pressure on said shaft element while preventing said wheel element and hub element from sliding past said spring.
Claim 2
Dependent Claim
225 words
In a toy building set, a wheel and shaft assembly comprising the combination of the following components made by injection molding of a thermoplastic material: a. A splined shaft element having a plurality of axially extending grooves forming ribs therebetween, said ribs having cylindrical outer surfaces coaxially disposed with respect to the shaft; b. An internally splined wheel element fitting the shaft element, so as to be slidably, but nonrotatably secured thereto, said wheel element comprising a disc-shaped member having at least one plane side face, a central bore in said plane side face defining a cylindrical recess in said discshaped member; c. An annular spring fitting into said cylindrical recess, the width of said annular spring being less than the depth of said cylindrical recess; and d. An internally splined hub element fitting the shaft element so as to be slidably, but nonrotatably mounted thereon adjacent the cylindrical recess in the disc-member, thereby defining a closed cylindrical cavity in said disc enclosing the said annular spring, said disc and hub elements being provided with means for mutually interlocking them, said spring being of a size such that, when said wheel element, spring and hub element are mounted on said shaft element, said spring exerts a radial pressure on said shaft element while preventing said wheel element and hub element from sliding past said spring.