Patent GB-186140-A (GB)
Title: Gear cutting machine
IPC: B23F1/04
Filed: 1921-06-20
Abstract: 186,140. Woodard, L. A., and Talbot, H. H. June 20, 1921. Gear-cutting; face-plates; mandrels.-In a machine for cutting helical or double-helical spur gears, particularly those of large size for rolling mills, the blank is mounted on a mandrel which is oscillated by means of a toothed sector directly engageable with the support while the tool is synchronously reciprocated across the face of the blank with automatic templet-controlled feed. The teeth are first roughed out by means of a milling-cutter and then finished by a planing-tool. The electric motor 75 drives through change gear. ing 77 and reduction gearing 78 a shaft 56, Fig. 10, located within a housing A and driving through spur gearing 80<g> and bevel-gearing 80b a shaft 80 carrying a worm 81 gearing with a rack 82 on the tool slide 6. The shaft 56 is further connected through change gearing 58 to a countershaft 52 driving through parallel shafts 41, 38, a worm engaging a toothed sector 35 on the blank carrier. The motor shaft 76 is reversed automatically so that through the above-described mechanism the tool is reciprocated synchronously with the oscillation of the blank, different helical angles being cut by modifications of the change-gears. The blank is mounted on a taper mandrel 10 by expanding bushings 16 and nut 17 and is clamped for further support to a face-plate 14. The opposite side of the face plate is secured to a spindle 13 in alignment with the mandrel 10 and loosely surrounded by a hollow sleeve 12 to which is secured a frame 23 carrying the toothed sector 35. This frame may be clamped to the faceplate by means of a bolt 31 engaging an annular T-slot 21 and secured to a sector 29, Fig. 5, actuated by a fluid-pressure operated rack 28. An extension 14a may be clamped to the face-plate by bolts 14c to accommodate blanks of large size, the clamping-mechanism and the blank-oscillating mechanism being correspondingly modified as shown by the dotted lines in Figs. 3 and 5. In operation the frame 23 is clamped to the faceplate so that the blank is oscillated during the cutting of a tooth. The tool T is fed forward automatically under the control of a former by means of adjustable stops on the table 7. After the completion of a tooth, the oscillating frame is unclamped and the blank indexed by means of a gear train 99 belt-driven from a separate motor 92 operating the indexing-wheel W rigidly secured to the spindle 13. Means are provided for disengaging the indexing-mechanism after the required angular movement has been imparted to the blank, and the oscillating frame is then again clamped to out the next tooth. For cutting helical teeth the blank is rotated by the oscillating mechanism while the tool travels across the outside face of the blank, while for double helical teeth one branch of all the teeth is first cut from front to centre of blank and the other branch is then cut from the centre to the rear face, the necessary reversal of the motion of the blank during cutting being effected by the bevel-gearing 80<b> in the tool-operating train. Straight teeth may be cut by disconnecting the oscillating mechanism.