Patent GB-554115-A (GB)
Title: Automatic gear grinding machine
IPC: B23F5/02
Filed: 1942-08-17
Abstract: 554,115. Gear cutting. FELLOWS GEAR SHAPER CO. Aug. 17, 1942, No. 11510. Convention date, Aug. 29, 1941. [Class 83 (iii)] [Also in Group XXIII] A machine for finishing gear teeth &c. by a generating motion of translation and rotation between the work and a cutting tool comprises reciprocating carriage and supporting structures, a rotatable work holder and a former coupled together being mounted on one structure, the former having opposite faces which engage abutments mounted, with the cutting tool, on the other structure, the abutments being adjustable angularly to set their contact faces at different angles to the path of the carriage to vary the angle through which the former is turned during a given extent of travel of the carriage, and also adjustable as to their distance apart to provide a variable lost motion, means being provided to maintain the former in contact with an abutment while the carriage moves in one direction and with the other in the opposite direction. The machine illustrated is hydraulically driven and controlled and comprises a fixed base 10, Fig. 1, having standards 11, 12 between which is a stool carrying two grinding wheels 14, 15, the standards being bridged by a work carriage resting on aligned guides and reciprocated while the work spindle is rotated so that the underside of the work 23 rolls across the adjacent rims of the grinding wheels. The grinding wheels are mounted on spindles 26, Fig. 18, driven by separate, resiliently coupled motors and carried by slides 29 adjustable by hand-actuated pinions 32 and riding on guides on the stool 16. The latter has a sleeve 39, Fig. 5, riding in a bearing 40 and is fitted with a worm 82 by means of which the stool may be adjusted angularly ; the stool is fixed in its adjusted position by a split metal band 41 having keys 44 riding in fixed vertical key-ways 46. Vertical adjustment of the stool is effected by a screw 50 coupled therewith and operated by a gear 60 and shaft 61 which is rotated step-by-step by an automatically-operated ratchet. The weight of the stool is taken by a piston head 55. The wheel dressers comprise a diamond 90 carried by an arm rotatable in a bearing 92 mounted in a guideway 94 and fed by an automaticallyoperated feed screw. The work spindle 20, Fig. 5, contains an internal sleeve 125 adjusted by a hand-operated screw 127 and carrying a spring centre 128 and driving key 129, engaging the work arbor 22. The tail stock 21 is carried by a bracket 132 along which it is adjusted by rack and pinion and is furnished with a centre 139 advanced by hand-operated screw and nut, or by hydraulic means. The bracket 132 can be swung to one side, to facilitate mounting the work, on a pivot 159 and is provided with a locking-bolt having interrupted threads. The translative component of the rolling movement of the work is effected by a motor comprising a piston 169 working in a cylinder 172 and a reversing valve 173 operated by adjustable dogs 174, 175. The rotative component is effected by a cam or former 177, Fig. 26, shaped like a gear tooth and mounted on a shaft 180 on the carriage, its faces co-operating with adjustable abutments 182, 183 carried on the base. The abutments comprise flattened bars clamped to segmental plates 181 pivoted to base plates 184, 185 and adjusted angularly thereon by worm gearing. The former is readily replaceable and is oscillated by a motor 199 operated, in step with the carriage reciprocating motor, to maintain the former in contact with one abutment in one direction of movement and with the other abutment in the other. The movement is transmitted to the work-spindle by an arm 201 and link 204 the latter being connected to an arm 202 connected by a pawl 205 to an index wheel 206 secured to the work spindle. At the end of each double reciprocation the work is rotated step by step by a motor, the admission valve of which is controlled simultaneously with the release of the pawl 205. Grinding is effected in a succession of stages by adjusting the distance between the abutments 178, 179. For this purpose, the abutment carriers 191, 192 are engaged by a lead screw 228 having clamped thereto a sleeve surrounded by a gear 234 meshing with a pinion 237 operated by a ratchet which is operated by actuators with varying strokes. The machine is driven by liquid pressure through control mechanism effecting automatically a cycle of operations till the work is finished.