Abstract: The known turn broaching of crankshaft main bearings is not suitable for broaching crankshaft bearing pins for the connecting rods because that would require locating the rotational axis of the crankshaft in the connecting rod bearing pins, whereby the crankshaft would rotate eccentrically. The resulting unbalances prevent driving the crankshaft with the r.p.m. required for the turn broaching operation. To avoid this problem a broaching lathe for the rotational or turn broaching of crankshaft connecting rod bearing pins is equipped with a steady rest including a rotating support device which permits mounting the crankshaft in the lathe in such a way that the rotational axis coincides with the axis of the connecting rod bearings of the crankshaft.

Abstract: The diameter of railroad wheels is calculated from data obtained by simultaneously producing two marker points on the tread surface of the wheel and simultaneously sensing these marker points and from data representing the known fixed location of the marker point generators and of the sensors. These data define a chord line and a chord height subtending the chord line. The length of the chord line and chord height in turn define the wheel diameter. A computer performs the calculations and provides a respective output that may be used for display or for controlling a tool such as a wheel truing machine.

Abstract: A broaching tool is provided with at least nine cutting tool edges arranged at its circumference. The cutting tool edges cover only a certain sector along the circumference of a tool disk while leaving another sector between a first and last cutting tool edge free of cutting tool edges. This feature enables moving a tool axially relative to a work piece without first moving the tool radially relative to the work piece. Further, the tool can be moved radially without damage. These movements are performed when the sector without cutting tool edges faces the work piece. This sector without cutting tool edges has an opening angle of less than 180.degree. and it provides a spacing and free space relative to a work piece. Thus, work piece surfaces that have been machined by the cutting edges, are free of these cutting edges if and when the other sector faces the work piece.

Abstract: Work pieces, especially of rotational symmetry, are machined in a rotary broaching operation. The machine tool for this purpose has a tool carrier carrying a plurality of cutting edges arranged on a curved path in a radial work piece plane. In order to reduce down-time and to simplify the construction of the broaching apparatus, the insertion of a work piece blank into the apparatus and the removal of a finished work piece from the apparatus are preferably performed without interrupting the motions of a tool carrier. For this purpose the tool carrier is provided with a zone which is free of cutting tool edges. This tool free zone of the tool carrier is located downstream of the last cutting edge as viewed in the rotational direction of the tool carrier. This feature avoids the need for a return stroke of the tool carrier. Accordingly, respective return slides and return controls are also obviated.