Vertical broaching machine for internal broaching

A vertical broaching machine for internal broaching, comprising:

• a base for mounting a blank being machined;
• a cross-piece supported for movement towards and away from said base;
• a mandrel having one end fixed to said cross-piece and one end supporting a broach;
• a spring collet positioned at the bottom of the broach and coaxial therewith, said collet centering a blank with respect to said broach during movement of the cross-piece towards the base;
• a guide supported by said base and located between said fixed end of said mandrel and said end supporting said broach;
• said guide having a passage for said mandrel in the course of said internal broaching of said blank;
• a hydraulic drive connected with said mandrel for imparting movement thereto, said base having uprights extending vertically upward therefrom and said guide being made as a traverse resting against said uprights and having said passage for said mandrel and two additional passages spaced at equal distances from said mandrel passage, said hydraulic drive including hydraulic cylinders having rods guided in said two additional passages of said traverse, each one of said hydraulic cylinders being located partly in the base and partly in one of said uprights, while the ends of said rods are interconnected above the traverse by the cross-piece supporting the mandrel.