Patent GB-778476-A (GB)
Title: Improvements in or relating to tooth cutting machines
IPC: B23F5/12
Filed: 1955-06-10
Abstract: 778,476. Gear-cutting. GLEASON WORKS. June 10, 1955 [June 15, 1954], No. 16781/55. Class 83 (3). A gear-tooth cutting machine comprises means on a tool support 11 for carrying a cutting-tool 14 in a substantially elliptical orbit in a plane approximately parallel to the tooth side-surface to be cut, the means being positioned on the support so that the tool moves in the direction of the major diameter of said orbit when it is at least approximately at the mid-point of its cutting and return strokes. The work G is mounted on a spindle 22 in a head 21 movable along the axis 16 on a base 18 adjustable angularly, about an axis 19 coincident with the axis 16 and the axis 12 of the tool cradle 11, on a slide 17 movable parallel to the axis 12. The cradle 11 carries plates 24 adjustable to set the tooth-angle by a turnbuckle 26 against scales 29. A plate 30 is adjustable on each plate 24 against a scale 34 for cone distance. A tool-head 13 is adjustable on each plate 30 against scales 38, 39 by a screw 37 to set the spacing of the tools to determine the width of tooth-slot cut and to set the tools in asymmetrical relation for cutting skew-bevel gears. Each disc-cutting tool 14 is clamped on a holder 40 journalled on an eccentric 51 on a spindle 47. Each holder 40 is pivoted at 42 to a swinging link 41 anchored by a pivot 45 to a bracket 44 adjustable about the axis 46 of the spindle 47. As the eccentric rotates, the tool describes an elliptically-shaped path 54. By adjusting the bracket 44 the direction of the major axis of the orbit is changed to enable the tool to represent a crown-gear or an internal or external bevel-gear. Non- generated gears and gears mating properly with non-generated gears may thus be cut, or toothbearing modifications introduced. The size of the orbit is adjusted by rotation of a shaft 55, carrying the eccentric 51, relatively to the spindle 47. Each tool is adjusted after sharpening by rotation of a worm 61 engaging teeth on the circumference of the tool. By setting each edge 15 at an angle A (less than 90 degrees), to the axis 46 of the spindle 47, the edge describes a concave path and so cuts crowned teeth. The tools are driven through speed change-gears, a shaft 69, shafts 75, 82 and gears 88. One gear 88 is connected to its spindle 47 by a sleeve 89 so that the gear 88 may be adjusted relatively to the eccentric 51 to enable the eccentrics to be correctly phased. The orbits of the tools may thus be adjusted so that one tool is at the middle of its cutting stroke while the other is at the middle of its return stroke. The cutting paths of the tools may slightiy overlap. The cradle is oscillated through a cam and a connecting rod. A feed-cam moves the work to cutting position at or prior to the beginning of a cutting-roll and withdraws the tools during a return-roll, a helical-motion cam causes an in- or out-feed during the roll to modify the pressure-angle on opposite sides of the teeth, and a further cam stops the machine when all the teeth have been cut. The machine may also be of the intermittent-indexing instead of the continuousindexing type.