Vertical spindle duplex head for a grinder

A vertical spindle duplex head for a grinder for grinding the end face of a workpiece to be rolled while rotating and revolving the workpiece, comprising a receiver wheel of an annular shape, a pressure wheel disposed above the receiver wheel, a pressing means for advancing and retreating the pressure wheel toward and from the receiver wheel, a rotary carrier for holding in a peripheral groove the workpiece to be put between the receiver wheel and the pressure wheel, an annular grindstone firmly held by a holding means concentrically with the rotary carrier, and a driving means for driving the receiver wheel and the pressure wheel to be rotated in opposite directions, characterized by:

• a distributive transmittance mechanism comprising a first driving shaft, a bearing housing of the frame supporting the first driving shaft, a first bevel gear fixed to a lower end of the driving shaft, a second shaft driven by a reduction gear through pulleys and a timing belt, a frame supporting said second shaft, a gear box formed integrally with the frame supporting the second shaft, a second bevel gear mounted on the second shaft, a third bevel gear engaging the first bevel gear and the second bevel gear at the same time, and a cover of the gear box rotatably supporting the third bevel gear;
• a differential gear mechanism comprising an input shaft with the third bevel gear mounted at an end thereof, a receiver wheel driving shaft supported by a bearing housing of the frame, a first gear of the receiver wheel driving shaft mounted at the lower end thereof, a second gear of an output shaft engaging the last mentioned first gear, said output shaft having the last mentioned second gear mounted at an end thereof, sun gears mounted opposite each other at the ends of the input shaft and the output shaft respectively, a pair of planet gears opposite each other engaging the sun gears, a planet gear shaft rotatably supporting the planet gears, a revolving gear case rotatably supporting the planet gear shaft and rotatably supported by the input shaft and the output shaft, and said gear box forming a bearing housing for the revolving gear case;
• and
• a variable-speed driving means comprising a worm gear mounted on the revolving gear case concentrically with the output shaft, a second worm gear engaging the first mentioned worm gear and supported by the frame, and a variable-speed motor for driving the second worm gear.