Abstract: A control apparatus for machine tools is provided which comprises a pulsed digital difference detector having one input connected to a digital branch and having a second input connected to a follower drive and having an output, an adding register having its input connected to the output of the pulsed digital difference detector, an analog nominal value source having its control input connected to the output of the adding register, and an analog branch having an input connected to the analog nominal value source and having its output connected to the input of the follower drive. A drive motor for the tool provides a signal to the digital branch and a drive motor for the blank forms part of the follower drive. The drive motor for the tool is a d.c. motor coupled to a velocity pickup, and cooperating with means for withdrawing the tool and a distance pickup coupled to the drive motor for the blank.

Abstract: The hobbing machine is formed with a work table housing enclosing a work table rotatable about a workpiece axis, and indexing gear system for driving the work table; a stationary stand supports for movement parallel to the work axis a hob carriage, the latter supporting a swivel head and a hob slide movable transversely to the work axis and carrying a hob spindle; a hob driving gear system, a separate feed driving system, a differential and differential change gears are arranged in the hob carriage whereas indexing change gears are arranged in the work table housing and coupled to the differential in the hob carriage.

Abstract: A hobbing machine for manufacturing spur and worm gears comprises a tool support provided with a support carriage movable in the direction of the axis of the blank to be machined and carrying a milling head provided with a separate feed drive which actuates via a branch gearing axial and tangential feed gear element and is connected via differential gears to a gear train for a hob. The branch gearing is arranged in the movable support carriage and includes a switch wheel which is engageable either with a drive wheel of the axial feed gear train or with the drive wheel of the tangential feed gear train and is controlled by a switching lever located on the support carriage.

Abstract: Pitch generation method for the production of bevel gears and mainly for the rough hobbing of pinions, with working of the pinion blank during generating of the tooth profiles, using a single cutter head for working both flanks of each tooth space. The generating speeds and ratio of roll of the cutter head, as well as the profile angle of the cutters are kept uniform. The desired, curved outlines of the tooth flanks, establishing a tapering tooth space, are generated by a simple mechanism which generates the proper motions of the gear cutters. For this purpose the cutter head is pivoted, opposite the workpiece or gear blank, in a drum, for several swiveling motions.