GB408094A - Apparatus for machining propeller blades - Google Patents

Abstract

408,094. Shaping helical surfaces. SCHIESS-DEFRIES AKT-GES., 114, K÷lner Strasse, D³sseldorf, Germany. March 14, 1933, No. 7774. Convention date, March 15, 1932. [Class 83 (iii).] In machining the rear surfaces of propeller blades on ordinary boring mills or centre lathes, the work being oscillated during machining and the tool being given a movement which produces a helical surface, additional means are provided to give the tool a controlled movement along a guide track to generate the required shape of the back of the blades. The tool is also given a rocking movement to maintain the cutting angle throughout the range of movement. When the additional movement is imparted to the tool in a direction perpendicular to the propeller axis, the usual rotary support on the transverse bar 1, Fig. 2 of a boring mill is replaced by a support 2 carrying a vertically movable saddle 3 on which the rocking tool-holder 6 is movable along guides 4 perpendicular to the work axis. In an alternative form, the vertically movable slide 9, Fig. 4, is transversely movable on a horizontal guide 4 adjustably mounted on the transverse bar 1 and carries the rocking tool holder 6. In another form, in which the work oscillates about a horizontal axis, the rocking tool holder is given the additional movement along a vertical slide on a saddle movable parallel to the work axis on a carriage guided transversely along the bed of the machine. When the additional movement is imparted to the tool in a direction normal to the curved back of a blade, i.e., always along a radius of curvature, the tool holder 6, Fig. 7, is slidable along a guide 4 on a saddle 3 which is pivoted at 11 to the vertically movable carriage 2, the movement along the guide 4 being always normal to the curved back X of the blade. The normal generating motion of the tool, the additional movement either perpendicular -to the work axis or along a radius of curvature of the blade surface, and also the rocking movement of the tool may be produced by a guide roller shaped according to the changing cross section of the blade, the connection between the roller and tool being preferably effected by means of a hydraulic servo-motor control of known construction, for maintaining the roller free from the pressure of the tool.