Patent GB-172383-A (GB)
Title: Grinding machine
IPC: B24B5/22
Filed: 1920-09-01
Abstract: 172,383. Sanford, F. C. Sept. 1, 1920. Rollers, spindles, rods, and the like, treating.- Comprises a centreless machine for grinding cylindrical bodies, in which the work is operated upon by a grinding-wheel and is fed axially, and rotated by a governing and feeding wheel, which is peripherally opposed to the grinding-wheel and rotates on an axis that may be set parallel or inclined to the axis of the grinding-wheel. Main frame. This comprises a base 1 and an upper section 2 having an horizontal bed 3 and a well 4. Two posts 5, Fig. 9, are provided, on the upper section, carrying split tapered bearing- sleeves 6, in which the shaft 7 of the grinding- wheel 8 is journaled. Grinding-wheel and mountings. The wheel 8 is secured on the shaft 7 by two annular members 19, 20 having wheel-gripping flanges 21. The member 19 has a screwed sleeve 22 pinned and keyed to the shaft and the member 20 screws on the sleeve. Governing and feeding wheel. The governing and feeding wheel 28, which is of abrading- material, is clamped on a spindle 31 between a collar 32 and a nut 34 with interposed discs 29, 30, Fig. 3. The spindle runs in slotted adjustable bearings 33 carried by extensions 38 of a yoke 35. The yoke comprises an annular plate 36, which is rotatably mounted on a boss 39 formed on a head 40, Fig. 2; the head is integral with, or secured to, a slide. 41 movable on ways on the table 3. The yoke may be adjusted rotatably angularly on the boss to set the spindle 31 at an angle to the horizontal to give automatic feed to the work. Work-rest. This comprises two supports 45, Fig. 14, carried by a plate 46 mounted on the slide 41, the supports being spaced apart to lie one on each side of the wheels 8, 28. Each support is slotted at 47 to receive a hard steel cylindrical rod 48, which is held in position by set-screws 49. The work makes line contact at c, d, e with the rod 48, the wheel 28, and the wheel 8 respectively. The rod 48 is arranged so that the axis of the work is somewhat below the plane containing the axis of the grinding-wheel 8 and the centre of the wheel 28, the point of contact e thus being above a diameter of the work parallel to that plane. The wheels 8, 28 both rotate in the same direction, but the grinding- wheel rotates at a higher speed than the feeding- wheel. Adjustment for work of different diameters. Work-supports of various heights are employed for different diameters of work and the plate 46 may be adjusted on the slide 41 to bring the axis of the bar 48 directly beneath the axis of the work. The governing and feeding wheel also is adjustable, towards and from the grinding-wheel, by movement of the slide 41 by means of a screwed rod 54 and a hand-wheel 57. Resilient pressure of the governing and feeding wheel on the work is secured by connecting the head 40 to the rod 54 through two compression springs 52, which may be adjusted to give different initial compressions. To obtain the last, and small, adjustment of the wheel, the head is tapped by a weighted arm 61 pivoted thereon. The work is guided between the wheels by angle-plates 64 adjustably secured to the supports 45. Prevention of chattering. Chattering and formation of flats on the work are prevented by a friction device comprising two arms 67, Fig. 1, pivoted to the arms 38 of the yoke 35 and provided with arcuate faces, lined with asbestos, wood. metal, &c., which bear on a collar 70 on the disc 30. The bearing pressure is varied by means of a bolt 72 carrying a spring and nuts 74. Feeding-wheel drive. The governing and feeding wheel may be driven at two speeds : a slow normal speed, and a higher speed for trueing the wheel. The wheel is driven, through a flexible or universally-jointed shaft 79, by a shaft 76, which is normally driven by a belt 82 and a pulley 80, Fig. 1, the pulley being loose on the shaft, but clutched thereto bv a roller clutch located in the hub of the pulley. When the shaft is driven at higher speed, by means of a pulley 81 and a belt 86 from the shaft 7, the clutch slips. Wheel-trueing device. To true the grinding and feeding wheels, the bar 48 is removed and guide-blocks 89, Fig. 16, are secured to the supports 45. A bar 92 is slidably mounted in the blocks and carries a holder 93 having a diamond or like point 94 at each end. The bar 92 is moved longitudinally, to true the wheels, by a lever 97. Water circulation and delivery. Water is supplied through a nozzle 101, Fig. 2, by a pump 103. After use the water flows from the well 4 into a tank 107 divided by a partition 111 into two sections. One section acts as a settling-tank and collects grit &c., and the water flowing over the partition is drawn off to the pump from the other section. Operation. The blanks to be ground are introduced between the wheels 8, 28 from one side of the machine, and are guided by the rod 48 and the plates 64. The work is rotated by the wheel 28, and also fed axially thereby when the axis of the wheel is inclined to the horizontal. Short bodies may be ground without axial advance bv setting the axis of the wheel 28 horizontal and placing the bodies between the wheels by hand. The axis of the grinding-wheel may be higher or lower than that of the feeding-wheel; the friction device for preventing chattering may comprise a single arm pressed against the collar, and the tapping-device may comprise a spring- supported weight or hammer.