| 摘要 |
1285317 Grinding KAPP & CO WERKZEUGMASCHINENFABRIK 19 April 1971 [16 July 1970] 27208/71 Heading B3D A dividing mechanism for a linear dividing table 1, for use in a machine for grinding a tooth rack 2, comprises first drive means for producing fine movement of the table, second drive means for producing coarse movement of the table, a common drive system for transmitting drive from the first and second drive means to the table, and control means for the first and second drive means to actuate each drive means to move the table by a predetermined distance. The table 1 is supported for movement on a bed (3, Fig. 4, not shown) by rollers (4, 5) and carries a rack 6 engaged by a positioning pinion 7 mounted on a shaft 8 having a worm wheel 9 engaged by a worm 10 on an output shaft 31 of a summation gear 30. The latter is connected to the spindle 22 of the coarse drive and, by reduction gearing 20 to the spindle 12 of the fine drive. The spindle 12 carries a dividing disc 11 and an impulsing disc 16 and is connected by a differential gear 13 to a high speed motor 14 and a low speed motor 15, the motors being arranged so that where one is driving the other is braked. The spindle 22, likewise, carries a dividing disc 21, impulsing dsic 26 and is connected by differential gear 23 to a high speed motor 24 and low speed motor 25, one of which is braked while the other is driven. Each dividing disc 11, 21 has notches 11a, 21a which are engaged by a roller 19, 29 on a lever 18, 28 which can be moved against a spring 34 by fluid pressure supplied to a cylinder 33 to disengage the roller from the disc. Each impulsing disc 16, 26 has markings 16a, 26a which are detected by a pulse signaller 17, 27 and fed to a controller. The latter has a counter 48 for counting the pulses from the signaller 17 and a second counter for counting the pulses from the signaller 27. When the number of pulses received by counter 48 is without a predetermined number of that set on the associated switch, the high speed motor of the associated coarse of fine drive is braked and the slow speed motors energized until the number on the counter almost equals that set on the switch whereupon the pressure in cylinder 33 allows the spring 34 to urge the roller 19, 29 into engagement with its dividing disc. When both rollers engage their discs, the indexing movement is complete. The distance between the notches of the fine drive disc 11 corresponds to a travel of 0À0001 mm. of the table 1 while that of the coarse disc 21 corresponds to 0À1 mm. travel of the table. During movement of the table, to reduce wear on the gearing, a thrust is applied to the table in the direction of movement by a pinion 45 driven by an hydraulic motor, the thrust being reversed on completion of the movement. Errors in the rack are corrected by a correction template 44 engaged by a follower lever 41 connected by levers 38, 39 acted on by a spring rocking an eccentric 37 engaging a bush 36, movement of the bush causing axial movement of the worm 10. |
