Patent GB-767342-A (GB)
Title: Improvements in or relating to piston ring making machine and process
Inventor: NORTON SAMUEL H
IPC: B23P15/06
Filed: 1954-09-15
Abstract: 767,342. Making piston-rings. THOMPSON PRODUCTS, Inc. Sept. 15,1954, No. 26770/54. Classes 83 (2) and 83 (4). [Also in Group XXIII] A method of making piston-rings from U-shaped stock with a transversely slotted web, Fig. 3, and spaced crowns 10, comprises thinning the ends of the crowns, coiling the stock into a helix with the crowns extending outwardly, setting the helix by heat treatment, grinding the outer peripheral surface of the segments to cylinder bore size and intermittently cutting the coiled stock into completed rings. Apparatus for carrying out the method, shown generally in Fig. 1, comprises a cold-rolling mill 16, an induction heater 17, a hot rolling mill 19, a shaft 20 about which the stock is coiled, a gauging device 21, heat treating furnace 25, grinding- machine 30 and a cut-off device 34. Rolling. The rolling-mill comprises two driven horizontal anvil rolls 65 and two vertical idle rolls 72, 101, Fig. 12. Each roll 65 has a lower flange 70 on which rests a limb of the stock and is secured to a vertical shaft 56 carrying at its lower end a spur gear 55. Gears 55 mesh with gears 54 on shafts 53 driven through worm gearing from a motor 39. The two shafts 56 are carried by bearing-blocks 59 and 60, Fig. 8, which are movable towards and away from each other by shafts 61, 62 having screwed portions of opposite hand and being rotatable through gearing by a hand wheel 87, Fig. 4, to vary the distance between the rolls 65. The roll 72 is tapered at 73 to form a taper on the ends of the crowns 10 and is journalled in blocks 76 adjustable vertically by a wedge device movable by a rack 82 and pinion 83, Fig. 7. The upper roll 101 is carried by an arm 103 pivoted at 105 and adjustable at its rear end by a screw 119. Stock approaches the rolls beneath a sprung guide-plate 109 and along a guide 108 which is adjustable both vertically and horizontally. On leaving the rolls, the stock passes along an adjustable guide 126 and is pulled through an induction heater 17 by the driven anvil rolls 154, Fig. 13, of the hot rolling mill. The rolls are driven from the motor 39 through a shaft 158 and gearing and are shaped to co-operate with an idle roll 155 which is tapered for the further thinning of the outer edges of the crowns 10. The anvil rolls are adjustable towards and away from each other and the roll 155 is adjustable in height in the same manner as the corresponding rolls of the cold rolling mill. Bending. As the stock leaves the mill 19 it is pushed into a shoe 171a, Fig. 14, having a curvature equal to that of the cylinders with which the rings are to be used. The crowns are held in engagement with the curved surface of the shoe by an upper adjustable grooved roll 174. A lower adjustable roll 171 is mounted in a recessed portion 171b of the shoe and engages the inside of the crowns. As the stock is bent, the pushing action of the rolls 154 moves the crown segments closer together. As the stock leaves the shoe it is bent backwards to open the slots 12 and then passes between adjustable rolls 176 and 179 which coil it to cylinder size on a shaft 20 with uniform gaps between adjacent ends of the crown segments. After leaving the roll 171 the strip is quenched by a medium supplied through a passage 200 in the arm 172 carrying the roll. The coiled strip moves axially along a driven mandrel 24 of an induction furnace 25 wherein it is set by heat treatment and then along a conveyer shaft 238 to the grinder 30 (see Group XXIII) and then to the cut-off device 34 (see Group XXIII) which severs ring lengths from the coiled stock. Indicating and controlling devices. Before entering the cold rolling mill, the stock passes beneath an indexing gear 124 so that the slots 12 in the web engage and drive the gear which in turn drives a stroboscopic disc 26, Fig. 16, arranged adjacent a fixed quadrant 148. A lamp 218 projects a beam of light through slits in the quadrant and disc to a mirror 219 and on to indicating-marks 215 and 214 on the shaft 20 and on a freely rotatable collar 21, Fig. 17, between the shaft 20 and mandrel 24 and driven by the coiled stock. The marks 215 enable the operator to detect a difference in speed between the indexing gear and the shaft 20. The collar 21 measures out during each revolution the amount of stock for one ring less the width of a cross-bar of the web, which is the amount the ring is stretched on the mandrel 24, plus the thickness of the wheel of the cut-off device 33. An increase or decrease in the speed of the collar indicates too much or too little thinning of the crowns in the rolling mills, which can be adjusted accordingly. Stock from the collar 21 is stretched on to the mandrel 24 of the furnace 25 by a gear 216 and a longitudinal key 237 which engage the slots 12 of the web, the gear 216 being surrounded by a helically-grooved annular guide 205. Specification 755,277 is referred to.