Machine tool head having nutating spindle

Claim 1

A nutatable-spindle machine-tool head comprising a head frame in the form of a housing having a front face, an elongated first rotary slide mounted for rotation in said head frame by a front face hub journalled in the front face of the head frame and by an axially remote, stabilizing tail bearing in the head frame, a second rotary slide mounted for rotation in the first rotary slide by a front face hub journalled in the front face hub of the first slide and by an axially remote, stabilizing tail bearing in the first slide, a spindle journalled in the face hub of said second slide and by an axially remote stabilizing tail bearing in the second slide, the axes of rotation of said spindle and of said two slides intersecting in a single point at the front of the spindle and closely adjacent the front face of the head frame with a common acute angle between the spindle axis and that of the second slide and between the axes of two slides, whereby the axis of a tool carried by the spindle can assume any position within a conical envelope having its apex at said point and having an apex angle four times the said common angle, a planetary gear train for driving the spindle and having a drive gear coaxial with said first rotary slide and a driven gear on the spindle and including at least two meshing pairs of bevel gears, and separate power means for turning said spindle drive gear and for positioning said rotary slides rotatively about their respective axis, the major part of the radial cutting load on said spindle being transmitted from slide to slide and to the head frame essentially in the plane of the front face of the head frame.