High-speed driving adapter for boring, milling and similar machine tools

In a high-speed driving adapter for boring, milling and similar machine tools, including:

• a gear housing which can be connected to a spindle housing of the machine tool so as to be fixed against rotation with respect thereto;
• a drive shaft which is supported rotatably in said gear housing and has a taper shank which fits into a conical receiving bore of a machine tool spindle of the machine tool;
• a bearing sleeve which is secured to a front end of said drive shaft;
• a tool-receiving spindle which is supported rotatably in said bearing sleeve and has a conical receiving bore for said tool taper shank of a boring or milling tool, which receiving bore is coaxial with respect to said drive shaft;
• and a sun-and-planet gear arrangement which is provided between said drive shaft and said tool-receiving spindle, an outer gear of said sun-and-planet gear arrangement being connected to said gear housing a sun gear of said sun-and-planet gear arrangement being connected to said tool-receiving spindle, and planetary wheels of said sun-and-planet gear arrangement being rotatably supported on said drive shaft;
• the improvement comprising wherein said sun gear is hollow thereby defining a cavity and concentrically surrounds said collect carrier, wherein a collect carrier is provided with a center ejecting pin and a collet and is axially movably supported in a coaxial bore in the tool-receiving spindle, said collet having ends which are constructed as claws and can engage an annular groove provided at the free end of a tool taper shank;
• wherein a cup spring arrangement is arranged concentrically with respect to said collet carrier and in said cavity in said sun gear, said cup spring arrangement urging said collet carrier away from said receiving bore;
• and wherein means are provided for releasing said collet and ejecting a tool taper shank, including a hydraulically actuated piston which acts onto said collet carrier in a direction opposite to the spring pressure and which is provided in a coaxial bore in said drive shaft.