Wheel frame

Abstract

A method of assembling a wheel rotatable about a main axis and having a plurality of peripheral rollers mounted on peripheral axles aligned tangentially about the wheel and radially spaced from the main axis, each peripheral axle joined to adjacent other peripheral axles to form a continuous ring comprising the peripheral axles, the method including the steps of: molding each peripheral axle in a die having a cylindrical cycle for forming the axle shaft of the peripheral axle without longitudinal separation tines, the peripheral axles each having a receiving head portion for receiving a free end of the axle shaft of an adjacent peripheral axle; mounting a roller on each axle shaft; joining the peripheral axles together to form a continuous ring of peripheral axles; and molding a wheel body including a support structure around the continuous ring.

What is claimed is: 
     
         1 . A wheel rotatable about a main axis and having a plurality of peripheral rollers mounted on peripheral axles aligned tangentially about said wheel and radially spaced from said main axis, each said peripheral axle:
 aligned normal to a corresponding radial line extending from the main axis;   having a head portion engaged to a shaft of an adjacent other peripheral axle, the peripheral axles together forming a continuous axle ring.   
     
     
         2 . A wheel according to  claim 1 , wherein each said peripheral axle is molded in a die that produces no mold parting lines extending longitudinally along an axle shaft of said peripheral axle. 
     
     
         3 . A wheel according to  claim 1 , wherein all or part of the length of an axle shaft of each said peripheral axle is molded in a die that defines a cylindrical cavity. 
     
     
         4 . A wheel according to  claim 3 , wherein a mold separation line extends laterally on said axle shaft, not longitudinally. 
     
     
         5 . A wheel according to  claim 3 , wherein each said peripheral axle comprises a head portion sized and configured to receive a free end of the axle shaft of an adjacent peripheral axle. 
     
     
         6 . A wheel according to  claim 5 , wherein said head portion defines a short bore to receive said free end. 
     
     
         7 . A wheel according to  claim 1 , wherein said peripheral axles are identical to one another. 
     
     
         8 . A wheel according to  claim 6 , wherein the axes of said short bore of said peripheral axle and said axle shaft of said adjacent peripheral axle are coaxial. 
     
     
         9 . A wheel according to  claim 6 , wherein the axes of the short bore of one of said peripheral axles and the axle shaft of the same peripheral axle are set at an angle theta determined by the algorithm 180−360/n, where n equals the number of peripheral rollers lying in a single plane on said continuous ring. 
     
     
         10 . A wheel according to  claim 6 , further comprising a wheel body with a hub defining a main axle bore and a plurality of outwardly extending supports on or in which said head portions are mounted. 
     
     
         11 . A wheel according to  claim 10 , wherein said wheel body is formed over said head portions. 
     
     
         12 . A method of assembling a wheel rotatable about a main axis and having a plurality of peripheral rollers mounted on peripheral axles aligned tangentially about said wheel and radially spaced from said main axis, each said peripheral axle joined to adjacent other peripheral axles to form a continuous ring comprising said peripheral axles, said method including the steps of:
 molding each peripheral axle in a die having a cylindrical cavity for forming the axle shaft of said peripheral axle without longitudinal separation lines, said peripheral axles each having a receiving head portion for receiving a free end of said axle shaft of an adjacent peripheral axle;   mounting a roller on each said axle shaft;   joining said peripheral axles together to form a continuous ring of peripheral axles; and   molding a wheel body including a support structure around said continuous ring.   
     
     
         13 . A method according to  claim 12 , wherein said wheel body includes a central hub to be rotatably mounted on a main axle. 
     
     
         14 . A method according to  claim 12 , wherein said support structure includes a plurality of outwardly extending arms that support said receiving heads in spaced relationship to the main axis. 
     
     
         15 . A method according to  claim 12 , wherein the step of mounting a roller on each said axle shaft is preceded by the step of mounting a bush as a sleeve over said axle shafts and the step of mounting the roller on each axle shaft includes inserting the axle shaft and the corresponding bush into a central longitudinal bore in said roller. 
     
     
         16 . A method according to  claim 12 , wherein said receiving head includes a spur that strengthens the joint between the receiving head and said wheel body. 
     
     
         17 . A method according to  claim 12 , wherein said receiving head includes a mouth defining a short bore, said mouth forming an annular shoulder on said axle shaft to trap the corresponding roller on said shaft between said receiving head and said mouth. 
     
     
         18 . A method according to  claim 16 , wherein said receiving head is in the form of a corner portion in which the longitudinal axis of the axle shaft is set at an angle theta to the longitudinal axis of the short bore, wherein theta is determined by the algorithm 180−360/n, where n equals the number of peripheral rollers lying in a single plane on said continuous ring. 
     
     
         19 . A method according to  claim 17 , wherein said die includes an additional cylindrical cavity for forming said mouth without forming longitudinal separation lines thereon. 
     
     
         20 . A wheel or method of manufacture therefor, substantially as hereinbefore described with reference to the accompanying drawings.