GB1253193A - - Google Patents

Abstract

1,253,193. Machine tool details. HAHN & KOLB K.G. 22 Jan., 1970 [23 Jan., 1969], No. 3147/70. Headings B3B and B3C. A machine tool for simultaneously working upon a plurality of workpieces, e.g. drilling, comprises an indexable turntable 12 which carries a plurality of work-holders (not shown) and a number of radially feedable tools (not shown) arranged around the turntable, the feed movement of the tools being produced by the rotation of cams 33. The cams are mounted on control shafts 20 which are rotated by an hydraulic motor 21 through a continuously operable central drive 23-26 and which are connected therewith by individual drive members 27-32. The turntable 12 is indexed in equal angular steps by an electric motor 13 driving through a worm and wheel 14, 15 to rotate a sinusoidal faced cam 16 which engages a pin 17 on a star wheel 18. The cam 16 is rotated one revolution for each indexing step. An hydraulic control is provided to drive the motor 21 at three speeds and a common control device is provided to control the three speeds and the indexing of the turntable, the said device including a cam-shaft rotated by a control shaft 20 to actuate switches. The three speeds relate to a cutting feed speed for the tool, a fast feed and retraction speed, and a slow speed effective during the indexing of the turntable. Each cam 33 is divided into sectors (73-76) (Fig. 3, not shown) which govern the tool feed to a dwell period (73) during indexing of the turntable, a fast feed (74) to the workpiece, a cutting speed (75), and a fast retraction (76). At the change over from one sector to another the cam-shaft operates a switch to change the speed of the motor 21 and hence of the rotation of the cam itself. Hydraulic control.-The three speeds of rotation of the motor 21 are achieved by providing two sources of hydraulic pressure, i.e. pumps 37 and 47, one pump providing the cutting speed, the other providing the slow speed and the two combining to produce the fast speed. Solenoid valves 43, 49 are controlled by the cain-shaft and switches previously mentioned. Non- return valves 46, 55, 57, flow regulators 45, 54 and pressure adjusting valves 39, 77 are provided A-solenoid operated shut-off valve 59 is controlled with the indexing of the turntable so that it is open only when the drive to the tools is on, and so that it shuts off if a fault develops in the indexing of the turntable.