Patent ID: 7044025
Filing Date: 2006-05-16
Classification: B27B

Abstract:
1. A rim sprocket for driving a saw chain of a chain saw, which rim sprocket is cast from molten steel in a batch casting process, said sprocket comprising: spaced apart side walls connected together by circumferentially spaced teeth, said side walls having an outer periphery for supporting side links of the saw chain and the circumferentially spaced apart teeth receiving and engaging center drive link tangs of the saw chain, and said side walls having an inner periphery configured to receive a splined drive shaft of the chain saw for rotatably driving the sprocket, and through engagement of the teeth with the drive link tangs thereby driving the saw chain of the chain saw; said side walls having continuous peripheral rings of metal defining said inner and outer peripheries and said side walls and teeth cooperatively configured to provide through bores between said teeth and extended through both side walls, said cooperatively configured side walls and teeth having a desired mass of material as compared to the outer surface area of the sprocket that is no greater than about 4 to 1 as measured in grams of weight to square inches of surface area.