GB807710A - Improvements in or relating to grinding attachments - Google Patents

Abstract

807,710. Internal grinding. M.S.O. MASCHINEN-UND SCHLEIFMITTELWERKE A.G. Aug. 26,1957 [Sept. 7,1956], No. 26865/57. Class 60. A grinding attachment adapted for connection to the spindle of a drilling machine comprises an internal grinding spindle 20, 21 which is carried by a bush 22 pivotally-connected by a pivot pin 23 to a bearing ring 24 arranged so as to be concentric with and driven by the drill spindle through a countershaft 7 and transmission means when the attachment is connected thereto, and a toothed rim 26 rotatably mounted by the bearing ring, coupled to the bush by a coupling pin 28, and arranged to be driven by the countershaft and transmission means at the same speed as the bearing ring. The countershaft, which is dispersed in a lateral extension 8 of a housing 2, is driven by gearing 4, 5, 6 from a shaft 3 coupled to the drill spindle and has secured to it a bush 9 with radial extensions 10, 11 on which are freely-rotatable bevel gears 12, 13. The gears engage, on one side of the bush, a bevel gear 14, which is rotatable on the shaft 7 and secured to a wheel 16 engaging a hand-controlled worm 17, and, on the other side a freelyrotatable bevel gear 15 secured to a gear 18 meshing with the toothed rim 26 which is rotatably-secured to the bearing ring 24 between lugs 29 formed in the bush 22 and extending into radial slots in the bearing ring. A further gear 19, secured to the shaft 7, engages a toothed rim 25 fixed to the bearing ring 24. The toothed rim 26 carries a pin 28 co-operating with a radial slot in a forked arm 27 provided on the bush 22 so that, with the countershaft 7 stationary, rotation of the worm 17 causes the gear 18 and the toothed rim 26 to rotate and the pin 28 to pivot the bush about the pin 23 in the bearing ring and radially displace the grinding wheel spindle : the amount of movement can be determined by a substantially-linearly graduated scale 30 associated with the worm 17. With the worm 17, and hence the gear 14, stationary, rotation of the countershaft 7 causes the bevel gears 12, 13 to drive the gear 18 at twice the speed of the shaft 7 and gear 19, but, since the velocity ratio between the gear 18 and rim 26 is twice that between the gear 19 and rim 25, both rims 25, 26 are driven at the same speed to rotate the bearing ring carrying the bush and grinding spindle. Additional movement to the gear 18 caused by rotation of the worm 17 adds to or substracts from the movement of the rim 26 to move the spindle radially inwards or outwards.