Patent GB-117078-A (GB)
Title: Improvements in or relating to Grinders.
IPC: B24B19/06
Filed: 1918-06-15
Abstract: 117,078. Rivett Lathe & Grinder Co., (Assignees of Halstead, F. H.). June 16, 1917, [Convention date]. Round holcs, enlarging and trucing; balls, shaping and surfacing; disk apparatus.-Consists of a machine for grinding the races of ball bearings, spherical surfaces, such as the parts of ball-andsocket joints, &c. The spindles 4 of the grinding- disk runs in a headstock mounted on top and bottom slides 16, 13, both extending transversely to the axis of the disk, the top slide being a positioning-slide and the lower the feed slide, and the work-spindle headstock 6, 7 is carried by a compound slide on the head 5 of a vertical shaft 10 and is swung to and fro in an are. For this purpose, the shaft carries a worm-wheel 41, which lies between a pair of worms mounted in a frame 46 and driven from a countershaft 23. The frame is pivoted at 45 and is swung to and fro in an horizontal plane, to bring one or other of the worms into gear with the worm-wheel, by means of tappets, on the oscillating head, that act through intermediate devices upon the free end 60 of the frame. The tappets are adjustable along a rib 63, which is concentric with the head. and they act upon dogs on a segment plate 66 having a limited amount of angular movements. An opening in the segment plate engages a pin 68 on a slide 69 that is formed with cams adapted to rock levers 72. The levers engage spring plungers in the end 60 and also control latches, which engage with claws on the same. The co-operating tappets and dogs are staggered so that each tappet will act only on the corresponding dog, whereby it is possible to provide for a swing of the head that is greater than the distance between the tappets. The screw 14 of the feed slide 13 is turned step by step by the oscillation of the worm-carrying frame 46. The frame in its movement rocks a short lever 84, Fig. 11, having on its free end a ridge 86, which wipes under a corresponding ridge on the head 89 of a vertical rod 88, which is thereby drawn up in opposition to a spring and, by means of a pawl on its head, turns the ratchet-wheel 91, Fig. 10, which drives the screw by a pinion and wheel 94, 95. The pawl is formed by a tooth at the end of a pin capable of sliding lengthways in the head 89 against the action of a spring. The pin may be turned on its axis to throw the pawl out of action. A train of wheels carried by a rocking support interposed between the pinion and wheel provides for reversal of the direction of rotation of the screw when desired. The feed movement may be reduced automatically step by step during the advance of the grinding-disk; or it may be kept constant at a determined rate ; or it may be kept constant up to a required point in the advance and then subjected to the automatic step-by-step reduction. Mounted beside the ratchet-wheel 91 and adapted to be clutched to it is a cam 101 bearing on the tail of a lever 107, which, on the other side of its fulcrum, is forked to embrace the rod 88 below its head 89 and thus serves to limit the descent of the rod and the pawl. The cam in its rotation gradually lifts the lever, reducing the stroke of the rod and the amount of the feed, until finally the ridges on the lever and rod are clear of each other and the feed ceases. By setting up the rod 88, by means of the net 111, so that initially its head stands above the lever 107, the feed will be at a constant rate until in the course of its rotation the cam has brought the lever up to the head. When the cam is locked in a fixed position, a constant feed is obtained. A stop-motion for the oscillating head is operated by the lever 107 of the feed mechanism; when this has been raised by the cam to stop the feed, it trips a catch to liberate a spring latch, which is then thrown into engagement with the worm frame. The frame of the machine is made in two parts; in the lower part is formed an oil well 56 that receives the worm gear and the lower bearing of the shaft 10; this bearing is carried by an arm 55 projecting downwards from the upper part of the frame, so that, by lifting the upper part, the shaft and the worm-wheel may be removed, leaving the worms and their frame in position in the lower part of the frame.