Patent GB-1371870-A (GB)
Title: Band grinding tool for rounding edge portions of blades for compressor  and turbine plants
IPC: B24B21/16
Filed: 1972-12-28
Abstract: 1371870 Grinding I L TASHKER 28 Dec 1972 59918/72 Heading B3D A machine for rounding the edge portions of a blade 8 for a compressor or turbine plant comprises a bed 1 mounting a mechanism for moving a grinding band 10 which is supported in the machining area by a contact member 13 having a reciprocating motion so as to provide interrupted grinding. and a device for securing a blade and feeding it to the machining area, the device having a support 2 which is mounted on the bed and movable to transversely feed the blade and which carries a movable head 4 having an attachment 6 for securing the blade in position, a blade profile 7, means for effecting synchronous oscillation of the blade and profile, the support being resiliently mounted on the bed such that profile 7 is biased against a profile cam 12, and means for rocking the head 4 with respect to the support 2 to provide movement of the point of contact between the cam and blade profile and between the blade and contact member. The support 2 is mounted by a pivot 3 on the bed 1 to permit the transverse feeding of the blade which is held by the attachment 6 on the head 4, the latter being mounted for pivotal movement by a hollow axle 5 on the support 2. The head also supports the profile 7 which is mounted for synchronous rotation with the blade 8 by means of a steel band 22 entrained around wheels 23, one of which is connected by a shaft 20 to the attachment 6 which is rotatable about an axle 18 and slidable along guides 19 for determining the initial position of the blade, and the other of which is secured to a shaft 21 connected both to the profile 7 and a gear 24 engaged by a quadrant 25 on a shaft 27 having a pinion 26 engaged by a vertically movable rack 28 disposed within the hollow axle 5. The rack is reciprocated by movement of an arm 29 about a shaft 30 by a cam 31. The blade 8 and profile 7 are rocked about a transverse axis K, Fig. 2, to effect a longitudinal movement of the point of contact of the blade with the abrasive band 10 running over the support cam 13 by rocking of the head 4 about the axis of the axle 5. The axle has an arm formed with a fork 52 engaged by a roller on a link 51 located in a slide 54 which is rockable about journals 55 in a fork 56 of a slide 57. The other end 49 of the link 51 is pivotally connected to a frame 46 rockable about journals 48 by a follower 47 engaging a cam 43. The slide 54 for the link 51 is movable along the link to vary the amplitude of oscillation of the head 4 by movement of an arm 58 connected by a link 59 to the slide about the shaft 30 by a cam 34 driven with the cam 31 by wheel 35 engaged by a worm 36 which is connected by gearing 44, 45 to the cam 43 so that the movement of the slide 54 along the link, the rocking of the link, and the reciprocation of the rack are synchronized to effect the oscillation of the blade and profile about axes 0, 01, rocking of the support 4 and hence the blade and profile about axes K, and variation of the degree of rocking. Rotation of the worm 36 driving the cams 31, 34 and 43 is effected through a telescopic link 38, gears Z4, Z7, Z8, Z9 of a switch over unit, and gears Z1 ... Z5 from a motor 40. The switch over unit can be moved to a position for driving a gear Z11 engaging a rack 69 connected by an arm 66 to a shaft 62 on which is a freely running roller 61 for the abrasive band and which is fixed to a bracket 65 supporting a tensioning roller 63. The arm 66 is also connected to an oil damper 70. The band 10 runs over a pulley 9 driven by a motor 11 which also drives a shaft 16 having an eccentric 15 which reciprocates the contact member 13 in the direction of the arrows b to effect intermittent grinding of the workpiece by the band 10. The contact member 12 is adjustable by a screw 14 on the bed 1 and the support 2 is resiliently urged towards the bed by a spring 17.