Patent GB-438767-A (GB)
Title: Improvements in or relating to gear-shaping machines
IPC: B23F5/16
Filed: 1935-03-07
Abstract: 438,767. Gear - cutting. McLEOD, R. J., c/o Power Plant Co., West Drayton, Middlesex. March 7, 1935, No. 7209. [Class 83 (iii)] In a gear-cutting machine of the reciprocating pinion-cutter type, particularly for cutting double-helical gears, by cutters which have a twisting movement during their reciprocation, the cutters are guided by two cylindrical helical guide members each connected to one of the cutters and arranged concentrically one within the other. The frame carries a column 12 and a table 14 for the blank 16. The cutterslide 18 is reciprocated by the usual crank 20 and carries a pair of heads in which the spindles 24, 25 of the pinion cutters 26, 27 are respectively mounted. The cutter 26 is connected by a hollow shaft 30 to an outer helical guide member 28 and the cutter 27 is connected to an inner helical guide 29 by a shaft 31 extending through the shaft 30. The outer guide member has a bearing in a housing 32 carried in a bearing bracket 34 and rotatable by the worm 37 of the generating mechanism. In the case of a horizontal machine the bracket may be provided with a foot piece which may constitute part of the machine base. In order to cause oscillation of the two guides when they are reciprocated and so impart the desired twist to the cutters, abutment shoes 140, 142 are secured within the housing 32. The helical guide faces are preferably arranged on the same side of the helix axis. The outer guide is reinforced at its open end by a ring 44. Preferably, the two-part outer abutment shoe 40, 41 is bolted to the housing 32 by bolts 49, while the inner shoe 42, 43 is bolted to the outer and to the housing by bolts 47 passing through slots in the outer shoe. The two parts of each shoe may be relatively adjusted to ensure correct fitting in the guides by means of studs 45, 46. One cutter is adjusted in relation to the other by adjusting the inner guide shoe longitudinally by means of rack-and-pinion gearing 50. The worm 37 which imparts generating movement to the guide members is driven through bevel gearing from a shaft 60 which is also connected through vertical shaft 57, bevel gears 62, change gearing 64, shaft 160, and worm gearing 65, to the blank table which is thus driven in unison with the cutters. In order to relieve the cutters from the work on the return strokes, a cam shaft 67 carries two cams 69, one for each cutter holder and the carrier 70 of the cutter spindle 24 is slidable in the head 22 which is fitted with a fixed rod 72. A block 74 having an inclined guide 76 engaging the carrier 70 is reciprocated along the rod 72 by the cam 69 thus moving the carrier 70 and cutter spindle to and from the work to give the required relieving and restoring movements. In order to permit this movement relatively to the helical guide members, the shafts 30, 31 controlled by the guides are journalled in brackets 86, 87 rigid with the heads 22 and are connected to their respective cutter spindles by members 89, 91 forming an Oldham coupling. The machine may be used for simultaneously cutting two helical gears, and the shoes 40, 42 may have the same opposite or different angles of inclination. According to the Provisional Specification, the cutters may be of the form described in Specification 437,365.