Chain wheel system

Chain wheel system comprising a drum having a circumferential periphery, tooth blocks secured to the circumferential periphery of said drum, a mating chain for engagement with said tooth blocks for driving said drum, said mating chain having spaced means for engaging said tooth blocks and driving said drum, wherein the improvement comprises that said tooth blocks are screwed to the circumferential periphery of said drum, said tooth blocks have a length in the circumferential periphery of said drum corresponding to at least one spacing of said spaced means, each said tooth block has a tooth crest located intermediate the ends thereof in the circumferential direction of said drum, the side of said tooth block facing said drum having a pair of grooves therein parallel to the axis of said drum, spacers fastened to the circumferential periphery of said drum and fitted into said grooves in said tooth block for adjusting the radially outer dimension of said tooth blocks relative to the axis of said drum, said spacers having a height dimension in the radial direction of said drum at least equal to the depth of said grooves into said tooth block, and said spacers are each of equal height and compensate for the difference between the diameter of said drum and the diameter required for a whole number of said tooth blocks.