Patent GB-407950-A (GB)
Title: Improvements in machines for producing helically toothed or fluted gears, cutters, hobs and the like
IPC: C10B37/02
Filed: 1932-08-26
Abstract: 407,950. Grinding gears, milling- cutters, &c. KLINGELNBERG, G. A., KLINGELNBERG, M., KLINGELNBERG, R. G., KLINGELNBERG, W. H., and KLINGELNBERG, H. W., (trading as KLINGENBERG SOHNE, W. F.), 56, Berghauser Strasse, Remscheid, Berghausen, Germany. Aug. 26, 1932, No. 33817. Convention date, Aug. 28, 1931. Divided on 406,730. [Class 60.] In a machine for relieving hobbing cutters, particularly cutters such as those described in Specification 406,730, the work is mounted on a table which is moved longitudinally by a lead-screw while the tool is mounted on a duplex transverse slide, one member of which is controlled to give the relieving movement while the other is so controlled as to produce a curved pitch line on the hob. The work 22, Fig. 2, is driven from a headstock 27 integral with the tailstock guides and mounted on a slide 28 moving on ways on aT-shaped bed 26, the slide being traversed by a leadscrew 31. The tool rest 33-34 comprises a lower slide 33 sliding transversely of the work axis on ways 39 and controlled by an hydraulic cylinder 41, Fig. 12, the travel towards the work being limited by an adjustable dog 45, Fig. 10, engaging a profiling cam 48. The dog is adjusted by means of a nut 46 and worm gearing 47 which may be operated either by hand or through a ratchet wheel actuated by a pawl controlled by an hydraulic cylinder so that a depth of cut feed may be applied while the work is on the return traverse. The movements of the slide 33 serve for adjusting the tool carried by the upper slide 34 to the depth of cut, for applying the feed and for withdrawing the tool for the return stroke. The upper slide also moves transversely of the work axis on circular guides 36 formed by a piston and cylinder, the hydraulic pressure in which forces the upper slide against a relieving cam. The tool attachment 35 carried by the slide 34 may be either a milling-cutter or grinding-wheel of the pencil or disc type or a turning tool of trapeziodal cross -section, rotary tools being driven from a motor either directly or through bevel or other gearing. A motor 60 which also drives an oil pump 123 supplying the hydraulic cylinders is connected through gearing, Fig. 3, with a high-speed bevel gear 68 and a slowspeed bevel gear 69, these gears being selectively locked to a shaft 73 by a friction clutch 72 operated by hydraulic cylinder 70 and lever 71. Spur gearing 75 connects the shaft 73 to a countershaft 76 carrying a worm 77 which drives the relieving cam. The shaft 76 is also connected through differential gearing 79, change gears, 80-83 bevel gears 88 shaft 90 and worm gearing 32 to the work-spindle. The shaft 84 of this train is connected through indexing change gears 91-94, shaft 95, indexing clutch 59, shaft 101, and change gears 99 to the lead-screw 31 which is thus driven in timed relation with the work. A branch train from the lead-screw drives a shaft connected by bevel gearing to the differential mechanism for relieving spiral fluted cutters. Further gearing, including change gears 51 shaft 55 and worm gearing 56 drives a shaft 58 carrying the profiling cam 48. The hydraulic pump is connected to a reversing control valve 125 operated by a lever 126 which may be controlled either by dogs on the work table or by hand. In one position of the lever 126, oil is passed into the pipe 129 thus actuating the reversing clutch lever 71 and actuating both the cylinders 42, 36, to force the slides against the relieving and profiling cams. On reversal of the lever the clutch 72 is shifted for the quick return and the tool is withdrawn from the work. During the return motion a grinding wheel may be automatically trued by a diamond tool and the depth of cut feed is applied. The profiling cam is arranged to rotate through a fraction of a revolution during the traverse of the work to enable hobbing cutters having concave pitch lines to be produced. The clutch 59 consists of a one revolution device which on reversal at the end of the working stroke delays the movement of the lead-screw while the work rotates for the required fraction of a revolution in cutting multiple threaded work. The shaft 98 carries a clutch member 102 while a clutch part 103 is mounted on the driven shaft 101 and its flange has an eccentric groove engaged by a bolt on cam plate 110 carried on an eccentric bearing 112 so that, by turning the cam plate, a catch 114 is moved so that it coacts with one or other of a pair of inwardly urged dogs 105, 106, carried by the clutch member 102. In one direction of rotation the dog 105 engages the catch 114 to drive the clutch member 103. On reversal the dog 105 disengages catch 114, the member 103 then ceasing to rotate until after nearly one revolution the dog 105 engages the catch and rotates the latter with the cam plate. This causes the catch 114 to move outwardly and the dog 105 trips over the catch while the second dog 106 engages the catch and restarts the clutch member 103. When another reversal occurs the catch and cam plate are returned to the initial position so that between the end of one work traverse and the restarting of the next traverse the shaft 98 acquires a lead of one revolution over the shaft 101. When the drive to the profiling cam is disconnected the machine may be used for relieving work with straight pitch surface generators, and if in addition the relief movement is suspended, single or multithreaded worms may be cut or ground. For relief grinding with a pencil grinding-wheel the attachment shown in Fig. 1 may be employed, the cone angle of the wheel being equal to the pressure angle of the teeth to be formed. Alternatively, a truncated conical disc 131, Fig. 15, may be employed, the disc being adjustable about a horizontal axis 134 and also about a vertical axis 135. In this way the disc may be adjusted to the pressure angle and to the helical angle of the work. Scales 141, 142 are provided to facilitate the angular adjustments. In both forms the grinding-wheel may be trued by a diamond operated by a hydraulic cylinder 120, which is adjustable to the flank angle of the wheel. The grinding-wheel is also movable manually towards the path of the trueing diamond to compensate for wheel wear.