GB186620A - Improvements in or relating to grinding machines - Google Patents

Abstract

186,620. Norton Co., (Assignees of Norton, C. H.). July 3, 1920, [Convention date]. Disc apparatus; trueing rotating tools. - The machine is of the type in which the rotating work is reciprocated past the grinding-wheel, and comprises a base made in two principal self-contained units, a work-base 20, Fig. 5, and a wheel-base 21, Fig. 6, adapted to be secured together; flexible connections are provided for transmitting power from one unit to the other. The machine is preferably driven by a motor 23, Fig. 6, from which a belt drives a main shaft 27. The grinding-wheel 30 is mounted on a shaft 31 driven through pulleys 32, 34 and a belt 33 from the shaft 27; a water-guard 28 is carried by the wheel slide 46. The belt 33 is kept tight by an idle pulley 35 carried by one arm of a bell-crank lever 36 and held up to the belt by a counterweight 37. The wheel is carried by a slide 46, movable on ways on the wheel-base, and is fed by a screw which is mounted in a chamber 50 in the base directly below cne of the ways and engages a half-nut on the slide. The screw is mounted near its ends in ball bearings and the thrust taken by an adjustable steel plug and by a steel plate. The screw is driven through gearing by a hand-wheel 60, Fig. 1, or by automatic mechanism. Change-speed mechanism for driving and traversing the work is contained in a box 115, Fig. 2, and power is taken from the shaft 27 to the box by a shaft 118 having universal joints 119 therein. The shaft is connected to a sleeve 120, Fig. 3, which is connected through a frictionclutch 121 to a hollow shaft 122; the clutch is normally held in engagement by a spring 127, the tension of which may be varied, the clutch being so set that abnormal resistance to the working of the machine causes slipping. Power is transmitted from the shaft 122 to a shaft 133, and from the left-hand end of the shaft 133 to the headstock and from the right-hand end to the work-traversing mechanism. For the traverse, six speeds are obtained by means of gears 136, 137, 141, sliding gears 140, and clutches 139, 143. The gears 141 drive the work-table through the clutch 143, a sprocket-wheel 146, a chain 147, a sprocket-wheel 148, a clutch, and reversing-gear. In order to obtain the slow traverse necessary for trueing the grinding-wheel to a fine finish, the clutch 143 is moved to the left, Fig. 2, when the table is traversed from the shaft 133 through gears 152, 153, 155, 156; the trueing-diamond 202, Fig. 10, is mounted in a carrier 201 attached to the tailstock 199 of the machine. The clutches and sliding gears are operated by three levers 164, 169, 173, shown at the right-hand end of the machine, Fig. 1, and the clutch yokes slide on a rod 158, Fig. 2. At the left of the machine are three levers, 187, 190, 191, two of which control the speed of rotation of the work, and the third the power supplied to the work and to the traverse; these levers operate clutches and sliding gears similar to those operating the traverse, and shown to the left of Fig. 2, whereby the work may be rotated at six different speeds. The work is rotated through a universally-jointed shaft 183. The main clutch 121 is operated, through a bellcrank lever 194 and a link 193, by the lever 191. The gears are so proportioned and arranged that when the two groups of levers 187, 190, and 173, 169 are in similar positions, the traverse and rotation of the work are so related that for a given width of grinding-wheel the work makes a complete revolution while the table traverses substantially one wheel width. Specifications 105,973, 118,515, 118,537 and 147,681 are referred to.