Patents Assigned to Firma Ernst Grob
  • Patent number: 4388818
    Abstract: An approximately shaped or formed gear is fabricated in any desired way and is then corrected by means of substantially ring-shaped rolls or rolling tools performing striking or hammering operations in the tooth gaps of such gear. The rolls rotate in a planetary fashion in revolving rolling or roller heads. Such rolling heads are advanced to a maximum radial penetration depth of the rolls which is governed by a stop and are then retracted, if necessary. The advance or feed is preferably performed by a hydraulic drive, the pressure of which is regulated electro-hydraulically by means of a template or the like. The hydraulic drive acts against the action of a spring. The approximately formed teeth, which are thus rolled in an overlapping manner, are produced by the addition of material per tooth flank. Preferably, such material addition amounts to at least twice or three-fold the summation pitch error according to DIN 3960 to 3962 (German Industrial Standard 3960 to 3962).
    Type: Grant
    Filed: September 4, 1981
    Date of Patent: June 21, 1983
    Assignee: Firma Ernst Grob
    Inventor: Hans Krapfenbauer
  • Patent number: 4307592
    Abstract: A cold rolling method wherein the workpiece is advanced along its lengthwise axis and rotated in pulsating fashion, in accordance with a sinusoidal-like rotational speed-time diagram, while its surface is machined during briefly effective individual rolling or generating operations by means of generating rolls seated in roller or rolling heads. Each rolling operation is accomplished when the rotational speed of the workpiece is at the lower reversal region of the aforementioned diagram. The cold rolling machine comprises a worm gear for rotating the workpiece together with its clamping or chucking device, the worm gear being seated upon the chucking device. The related worm is mounted in a displaceable carriage. This carriage is moved to-and-fro by an eccentric drive or equivalent structure, and the action of the worm is superimposed upon the worm gear and there is formed the sinusoidal-like course of the rotational speed as a function of time.
    Type: Grant
    Filed: August 24, 1979
    Date of Patent: December 29, 1981
    Assignee: Firma Ernst Grob
    Inventor: Hans Krapfenbauer