Patent GB-472495-A (GB)
Title: Improvements in methods of and apparatus for cutting grooved rolls
IPC: B23B5/10
Filed: 1936-03-23
Abstract: 472,495. Turning and grinding grooved rolls. BECKER, H. March 23, 1936, No. 8683. [Classes 83 (ii) and 83 (iii)] [Also in Group XXIII] Lathes.-In turning grooved rolls 4 such as those used for rolling tubes, a cutting or grinding tool is set radially to the roll axis and is reciprocated axially of the roll during its rotation according to the varying breadth of the roll groove and also reciprocated radially at the same time according to the varying depth of the roll groove. The roll 4 is mounted between a headstock 2 and tail-centre 3 above a frame portion 5 which carries a rotatable table 6 having guides for a slide rest 7 provided with a pin 8 on which the tool rest 9 is pivotally mounted. The tool rest has a forked rear projection 11 engaging over a fixed roller 12 so that the tool 14 which has an arcuate cutting edge 15 is always maintained approximately radial to the work axis. A gear on the work spindle drives through differential gearing and bevel gearing 24, a cam 27 acting on a roller 29 on the slide rest 7, the cam rotating synchronously with the work. The shaft 30 of this gearing drives a crank disc 31 operating a ratchet wheel 34 on a shaft 35 which is connected by gearing to the table 6 and by gearing 38 to the casing of the differential gearing. The roll 4, Fig. 5, preferably having its groove preformed by turning, pressing, forging or the like, is mounted so that the axis of the table 6 is tangential to the roll periphery while the centre of curvature of the tool edge lies in the axis 44 of the pin 8. In operation, in the position of the tool shown in Fig. 5, the table is located so that the cam 27 moves the tool along the line 47 in a half revolution of the work from the position shown in Fig. 5, to that shown in Fig. 6. By the table feed mechanism the tool edge centre 44 is fed round the axis 43 and the roller 29 is moved round the cam, whose rotation is compensated by the differential gearing so that its major axis always lies in the direction of the slide rest 7. Fig. 9 shows the position when three-quarters of the profile has been turned, the tool being reciprocated along the line 47 to vary the size of the roll groove. In a modification, Fig. 11, the tool slide consists of two relatively adjustable parts 51, 52 and the slide rest also consists of two relatively adjustable parts 48, 49. In this form, by adjusting the parts 51, 52 so that the tool edge centre is set back relatively to the centre 43 an elliptical groove, Fig. 14, is produced whereof the major axis is at light angles to the roll axis. Similarly by setting the tool edge forwardly relative to the centre 43 an elliptical groove having the major axis parallel to the roll axis is produced. In another modification, Fig. 17, the fixed roller 12 is replaced by a roller 55 adjustable on a crank disc 54 on the opposite side of the work. The crank disc is driven, either from the cam 27 or from the table 6 through gearing 60. When the gearing 60 is in operation the crank disc causes the tool to oscillate between the positions shown in Fig. 17 while the groove is turned so that inclined sides are produced on the groove, the inclination varying with the setting of the crank disc. If the gearing from cam 27 is employed the crank disc rotates synchronously with the cam so that the tool changes its angularity in passing from the wide to the narrow part of the groove. In this way only the wide part of the groove has a bevelled flank. By changing the roller 55 to the opposite side of its groove, Fig. 17, and using the gearing 60, a groove without flank bevelling may be formed. The shape of the groove may be altered by changing the form of the tool cutting edge. In a modification, Fig. 18, for grinding the roll profile, a support 70 fixed to the member 10 carries a grinding wheel 71 driven from a motor 74, the motor and wheel partaking of the above described movements of the plate 9.