GB424261A - Improvements in internal grinding machines - Google Patents

Abstract

424,261. Internal-grinding machines. CHURCHILL MACHINE TOOL CO., Ltd., Broadheath, near Manchester, and ASBRIDGE, H. H., Reigate, Moss Lane, Ashton-on-Mersey. July 19, 1933, No. 20361. [Class 60] The worktable of an internalgrinding machine when moving to grinding position connects the driving means to a mechanism for a mechanically timed cycle of operations which proceeds to its completion independently of further movements of the table, the mechanism comprising means to control the feeding of the grinding wheel to and from the work, and a tappet wheel which makes one revolution during the cycle and controls feed compensation for wheel wear, the reversal of the worktable, and disconnection of the drive to the mechanism at the end of the cycle. In the grinder shown, the worktable a is moved to grinding position by hand operation of the reversing handle s controlling the flow of fluid to the hydraulic operating cylinder, and is then reciprocated during grinding by a mechanically-oscillated stop c which engages an abutment d on the table, as described in Specification 415,879. When grinding position is reached, a dog p on the table engages a lever t and causes it to raise a drop-worm w, carried by pivoted arms v, Fig. 2, and driven by a belt w<1>, into engagement with a worm-wheel 2. The worm is retained in this position by a rod x pivoted to the lever t and having a recess in which engages a locking slide when it is in the raised position. On the shaft 3 of the worm is a face-cam 4, Fig. 2, against which a pin 7 on the cross-slide 5 of the wheel head is caused to bear by a weight 8, and which causes the in and out feed movements of the slide. Also mounted on the shaft 3 is the wheel 9, carrying tappets 10, 14, 22. During rotation of this wheel the tappet 14 engages a sliding rod 15, Fig. 1, which operates through a pawl 16 and ratchet wheel 17 a worm 18, Fig. 2, and through it a worm wheel 19 which rotates a sleeve 20 revoluble on the shaft 3 and having a screwed end engaging a nut 21 against which the cam 4 bears. The nut and cam are thus moved axially to compensate for wheel wear. On completion of grinding, the tappet 10 engages a plunger 11, which through a lever 12 and link 13 reverses the handle s and causes the table a to be moved away, a dog q on the table bringing the handle to neutral position at the end of the stroke. Finally, the tappet 22 on the wheel 9 causes the locking-slide to release the rod x, which drops and allows the worm w to disengage from the wheel 2. During movement of the table to grinding position, a tappet 25, Fig. 5, on it causes fluid to be supplied to a cylinder k which causes rotation about an axis j of a wheel trueing tool and brings it into the operative position shown in full lines.