Homelite was making one-man saws early on. This model was called a "5-20" because it was supposed to produce 5 horsepower, yet weigh only 20 pounds. Note that it is a gear drive saw. Unlike the saws of today, there is a gear train between the engine and the chain drive sprocket. It used big chain and pulled it slowly, but with tremendous "guts". From the Leonard's Mills Forest and Logging Museum.
Van Nattas got their first Homelite in the late 1950's. It was gear drive very similar to this in appearance except that it was blue in color. We used it for many years. It is not completely clear to this writer why the manufacturers thought they needed a gear reduction in them other than perhaps to reduce the wear on the bars and chains. Automatic oilers were not common and the roller nose bars had not been invented (or at least those without a stinger). Ultimately, the gear drive saw came to be recognized as a safety hazard because if the top of the bar pinched the tremendous torque of the saw would push the saw backwards. More than one logger has told of suddenly finding himself laying flat on his back with the saw laying on his belly. This was particularly an issue when a very long bar was being used. The direct drive saws have less torque and are easier for the operator to 'stall' in case of a pinch, and in recent years a chain brake has been added as a safety device to manage the 'kick back' issue. The chain brake is usually a lever mounted just in front of the front handle bar. If the saw is 'kicked back' the operator's hand engages the brake stopping the chain hopefully before the operator is thrown backwards.