Overload protection system for multi-speed machines

Claim 1

Apparatus for driving different cutting tools for cutting materials having regions of abnormal hardness exposing cutting tools to overload conditions and breakage, comprising in combination: a drive motor having an output shaft for supplying driving power; means for adapting said driving power to different cutting tools and materials, including changeable speed first gear means having output means for driving any of said tools and having input means; means for immersing at least part of said first gear means in a lubricant; second gear means having input means connected directly to said drive motor output shaft, having first output means connected to said input means of said changeable speed first gear means, and having second output means; overload responsive brake means connected to said second output means of said second gear means for braking said second output means until occurrence of an overload condition, and for releasing said second output means upon occurrence of an overload condition to safeguard the particular cutting tool and the drive motor against damage; and means extending from said first to said second gear means for supplying lubricant to said brake means.